Saturday, December 23, 2006

Wireless power for all your Christmas presents!!!!

1) Power from mains to antenna, which is made of copper
2) Antenna resonates at a frequency of 6.4MHz, emitting electromagnetic waves
3) 'Tails' of energy from antenna 'tunnel' up to 5m (16.4ft)
4) Electricity picked up by laptop's antenna, which must also be resonating at 6.4MHz. Energy used to re-charge device
5) Energy not transferred to laptop re-absorbed by source antenna. People/other objects not affected as not resonating at 6.4MHz

More details on this link: http://news.bbc.co.uk/1/hi/technology/6129460.stm

Thursday, December 21, 2006

Monday, December 18, 2006

Could Santa deliver gifts to all the world's children in one night?

Of course he can, with help from Nasa, Einstein and 360,000 reindeer. Scientists have been wrestling with the feasibility of Santa's job description since the 1850s. The latest thinking is that delivering one kilogram of presents to the world's 2.1 billion children (regardless of religious denomination) is entirely realistic, with a little lateral thinking.

Scientists at the American space agency, Nasa, reckon the man from Lapland relies on an antenna that picks up electromagnetic signals from children's brains to know what presents they want. Assuming an average of 2.5 children per house Mr Claus must make 842 million stops tonight to fill his orders.

By allowing a quarter of a mile between each stop, he must travel 218 million miles with about a thousandth of a second to squeeze down each chimney, unload a stocking, eat a mince pie, swig cooking sherry and get his sleigh airborne again. To achieve this he must travel at 1,280 miles per second. Travelling east to west, he can stretch Christmas Day to 31 hours.

To have enough presents, Santa's sleigh must carry 400,000 ton of gifts. With the average non-turbocharged reindeer capable of pulling only 150kg, Father Christmas would need 360,000 reindeer to heave his vehicle skyward.

The cavalcade would have a mass of about 500,000 tons which, at the required speed, would cause each reindeer to vaporise in a sonic boom flattening every tree and building within 30 miles. Father Christmas would have a mass of two million kilograms, causing him to combust when his reindeer come to their sudden halt. Piffle.

First, Einstein's theory of relativity dictates that the faster an object travels, the slower time appears to pass. So at the speed he is travelling, .0001 of a second allows Santa to perform his tasks at leisure pace. Second, as an expert in quantum physics, Mr Claus knows wormholes in the fabric of universe allow him to move instantly from one dimension and place to another. His sleigh is a time-machine powered by an unknown fuel which any economy on the world would have on its Christmas list.

Tuesday, December 12, 2006

Grow your own stalactite - yes, honestly it can be done, and it looks like an icicle, handy as a decoration for the coming festivities.

You will need:

Salt
Two small jars
Large paper clips
Wool or string
A small saucer.

What to do:

Stir plenty of salt into a large glass of very hot water. Keep stirring. If all the salt dissolves, add more. Allow to cool, then pour half into each jar.
Attach a paper clip to each end of a piece of wool - about 40 cm long.
Put one end of the wool in one of the bottles, and the other end of the wool in the other bottle. Make sure the ends of the wool are in the solution.
Now make sure that the bottom of the loop of wool between the bottles is hanging below the level of the salt solution in the bottles.
Place a saucer under the bottom of the loop of wool. Leave for a week.

What’s going on?

The salt solution travels along the wool by capillary action. This is a physical effect by which water can travel upwards as if to defy gravity! It is due to the interactions between the water molecules and the wool which contains tiny tubes and spaces for the solution to fill. Plants take advantage of capillary action to pull water from the soil into themselves.

As the salt solution travels along the wool it starts to drip off the lowest point of the loop of wool. The water evaporates and salt crystals are left behind. In time more and more salt solution drips down and the crystals of salt grow larger. Eventually it forms a stalactite.

Stalactites and stalagmites, collectively known as speleothems, form due to water seeping through rock. As the water moves through the rock, it dissolves small amounts of limestone or calcium carbonate. When the water drips from a cave ceiling, small amounts of this limestone are left behind, eventually leaving an icicle shaped stalactite. Limestone that reaches the cave floor "piles up" and forms stalagmites.

Frosted glass

Do you remember the days before central heating? Jack Frost painting pretty pictures on the windowpanes? No? Well lucky you! Anyway it is all due to the formation of crystals. Try it for yourself.

You will need:

glass jam jar
glass bottle or jar
Epsom salts (magnesium sulphate) available from chemist shops
water
paint brush

What to do:


Dissolve Epsom salts (magnesium sulphate) in a jam jar of hot water until no more will dissolve.
Brush a small amount of the liquid onto the bottle or jar.
Leave for 15 minutes or so and the liquid will quickly evaporate, leaving behind a patchy pattern of delicate crystals.
When it is dry, paint on another layer and continue until the glass or jar is covered with a film of beautiful needle shaped crystals.

What's going on?

Epsom salts is a common name for magnesium sulphate heptahydrate, MgSO4·7H2O, a water-soluble bitter-tasting compound that occurs as white or colourless needle-shaped crystals. It was first prepared from the waters of mineral springs at Epsom, England; it also occurs as the mineral epsomite. Epsom salts are used medicinally as a purgative; hence the phrase "through you like a dose of salts"!
The salt solution is called 'saturated' - it is holding as much salt as it possibly can. As some of the water slowly evaporates, the water that's left can't hold all the dissolved salt. The Epsom salts recrystallise and appear as an intricate pattern of needle shaped crystals on the glass surface.
Crystals are a 3-dimensional organised array of atoms or molecules. They grow in particular shapes depending on how each face of the crystal develops. Magnesium sulphate is orthorhombic in shape. In some cases other crystals start to form on top of the faces to give extraordinary patterns such as those seen in snowflakes.

Exploding Oatcakes - more energy than TNT!!!!!!!

Hard to believe? The facts are easy to find. From published data, we can find that TNT yields about 4.25 megajoules of energy per kilogram when detonated, fairly typical for a high explosive.

Next, off to the kitchen cupboard. The oatcake packet tells me that oatcakes yield 18 megajoules per kilogram. This is more than 4 times as much energy as in the TNT.

So why are oatcakes so much less spectacular than TNT? It's because explosions are not so much about releasing a lot of energy, they're about releasing it very quickly. TNT certainly does that – an oatcake-sized amount of TNT releases its energy in a fraction of a microsecond. This creates huge gas pressures, and hence an explosion. An oatcake, on the other hand, takes minutes to burn.

Now there's one thing I haven't mentioned. Explosives include everything needed for the reactions that make them go bang, but an oatcake needs a source of oxygen. We really ought to include the mass of the oxygen along with the mass of the oatcake. The packet says that oatcakes contain a lot of carbohydrate, with about a third as much fat. Carbohydrate needs about its own mass of oxygen to burn, and fat needs about 3-4 times as much. It works out that a burning oatcake consumes about 1.5 times its own mass in oxygen. So the 18 megajoules that we get from a kilogram of oatcakes actually comes from about 2.5 kilograms of material. Even so, it still beats TNT.

There's another important factor: whereas the chemicals in explosives are already exactly in position and ready for action, the oxygen that an oatcake needs is not inside the oatcake. The rate at which the oatcake burns depends on how fast we can supply oxygen. If we could somehow incorporate enough oxygen right inside the oatcake, it might indeed go off with a bang. Would that make it a cracker?

Can a pressure washer peel off your skin - watch and find out!

Wednesday, December 6, 2006

Cloud in a jar

They say every cloud has a silver lining. Maybe it’s time to find out.

Adult supervision required

You will need:

Matches
Glass jar
Small bag of ice
Hot water
Black paper (optional)
Sticky tape to secure the black paper around the back of the jar (optional)

What to do:

Cut a small piece of black paper and secure it around the back of the jar with sticky tape. This helps us “see” the cloud better.
Pour hot water into the jar until is 1⁄4 full.
Light a match, place it over the opening of the jar and blow it out. (this must be done by an adult).
Wait a second or two then drop the match into the water inside the jar.
Quickly place the bag of ice on top of the jar covering the opening. Make sure the ice does not go down into the jar but just across the top.
Watch as the cloud begins to form!
Lift the ice and watch the cloud come out. COOL! Now’s your chance to grab it and check whether it has a silver lining. Good luck with that!

What’s going on?


The warm water heats the layer of air that it touches. Some of the water evaporates into the air forming water vapour. The warm air containing water vapour rises, and then cools, as it comes in contact with the air cooled by the ice. When the water molecules cool, they slow down and stick together more readily. The particles of smoke act as nuclei for “bunches” of water molecules to collect on. This process is called condensation.

Clouds in the real world form in a similar way to the one created in the jam jar. As the atmosphere (air) cools, water vapour suspended in the atmosphere condenses into water droplets around condensation nuclei (tiny particles of dust, ash, pollutants, and even sea salt).

In this experiment the ice is used to cool the air, however, in the real world the main cause for cooling air is to force it to rise. As air rises it expands - because the pressure decreases through the atmosphere - and therefore cools. Eventually it may become saturated and the water vapour then condenses into tiny water droplets, similar in size to those found in fog, and forms cloud. If the temperature reaches below about -20 °C, many of the cloud droplets will have frozen so that the cloud is mainly composed of ice crystals.

Why does a champagne bottle have a concave bottom?

Monday, December 4, 2006

IB Physics trip to Dreamworld

No comments please! The year 12 biologists are out on their field trip at the moment (no wonder it is so quiet) and you may be wondering if the physicists go somewhere. Well, a couple of weekends back they went measuring, recording, calculating and experimenting (including measuring the g-force of each ride with a home made g-force device) at dreamworld. Mr Roff asked for them to send some interesting photos and this is what he they sent him. Who said physics was boring?

Wednesday, November 22, 2006

Tuesday, November 21, 2006

Monday, November 20, 2006

Saturday, November 18, 2006

Ever wondered how a fire extinguisher works?

Secret Messages

There are many ways of hiding a message and we’ve found four of them. The choice – Mr Bond – is yours…

You will need:

Candle or white wax crayon
Paper
Water-based paint
Cotton buds
Lemon juice
Bicarbonate of soda
Red cabbage water (see instructions)
Pencil
Paintbrush

What to do:

Method 1: Candle or wax crayon
Write your message on a piece of paper using the candle or crayon. Can you see it? No of course not!
Now paint over the message with water based paint. See the message now? Aha!

Method 2: Lemon juice
Write your message on a piece of paper using a cotton bud dipped in lemon juice. See the message? No.
Now either iron over the message or place it near a light bulb (help children to do this). We don’t want anyone getting burnt! See the message now? Oooh yes! And it’s gone brown!

Method 3: Pencil and wet paper
Wet some paper, just a bit, and place another sheet of paper on top. Use the pencil to write your message quite gently.
Take the topmost paper off. Wait for the wet paper to dry. Can you see your message? No (sounding a little irritated at being ask the same thing over and over).
Now wet the paper again. Well would you believe it? There’s the message.

Method 4: Bicarbonate of soda and red cabbage water
Dissolve two teaspoons of bicarbonate of soda in four tablespoons of warm water.
Write your message on the paper using a cotton bud dipped in the solution.
Let it dry. Can you see it? Sigh. No. And it’s not funny any more.
Pour hot water over some shredded red cabbage leaves. Leave for 15 mins and then strain. You should have a dark purple solution.
Paint the red cabbage water over your message. Well I never!
Try it again but this time use lemon juice instead of bicarbonate of soda.

What’s going on?

Method 1: Candle or wax crayon
Wax is oil based and oil and water do not mix. The paint will not stick to the wax message so the paint soaks into the paper and leaves the waxy areas paint-free. Your message will show up white against a coloured background.

Method 2: Lemon juice
The lemon juice is very nearly clear so does not show up on the paper when it is dry. When you heat the paper, the lemon juice starts to burn. Like all organic material (i.e. anything that was once living), the lemon juice contains carbon. When it burns, some of the carbon is released in the same way a candle releases soot. The brown writing is just the carbon that has come out of the charred lemon juice.

Method 3: Pencil and wet paper
The pressure from your pencil will mash up the fibres on the lower, damp sheet of paper. Mashed up fibres reflect the light differently to normal, unmashed fibres. But when the paper dries, the fibres look the same, so your message disappears - until you wet the paper again.

Method 4: Bicarbonate of soda and red cabbage water
Red cabbage water is a dark purple colour. It is a natural indicator which means it changes colour in the presence of acids or alkalis. With acids it turns red or pink and with alkalis it turns blue or green. Bicarbonate of soda is alkaline and when the red cabbage water is painted on it turns blue and shows up against the purple background. If you use lemon juice instead the message will appear red against a purple background.

Tuesday, November 14, 2006

Spooky numbers



Halloween has been and gone but this one remains intriguing - can you tell us how it works? Comments welcome! Turn on your speakers.

Friday, November 10, 2006

How good is your hand - eye coordination?



Co-science B10 Coordination and Response - how quickly can you park this car? 20 seconds is my best - post your time!

Wednesday, November 8, 2006

The Nucleus Game



Ok, I had several complaints that the last game wasted your time. Try this one then - it gets difficult when you start to make covalent bonds (sharing electrons). See for yourself.

Monday, November 6, 2006

Year 7 Tutorial - Anti Smoking


Around 114,000 people in the UK die every year as a result of smoking-related illnesses. Cigarettes contain around 4000 different chemicals, either gases or particles - the most additive of which is nicotine. Nicotine reaches the brain within 20 seconds and creates a dependency. In their tutorial Year 7 students will see the harmful chemical produced in just a single cigarette - ask them to tell you what they found out. Click this link to find out more:

Saturday, November 4, 2006

Teen repellent

A device that repels teenagers has won the peace prize at this year's Ig Nobels - the spoof alternative to the rather more sober Nobel prizes. Welshman Howard Stapleton's device makes a high-pitched noise inaudible to adults but annoying to teenagers.

Other winners included a US-Israeli study into how a finger up the rectum cures hiccups and a report into why woodpeckers do not get headaches.

All the research is real and published in often prestigious journals.

Unlike the recipients of the more illustrious awards, Ig Nobel winners get no cash reward.

Nevertheless eight of the 10 winners this year paid their own way to receive their prizes in Cambridge, Massachusetts.

Marc Abrahams, editor of science humour magazine Annals of Improbable Research, which co-sponsors the awards, said: "The prizes are intended to celebrate the unusual, honour the imaginative - and spur people's interest in science, medicine and technology."

Real-life Nobel Laureates demonstrated winning research
The winners are given a one-minute acceptance speech, the time policed by a loud eight-year-old girl.

This year's winners included:

Maths: How many photos must be taken to almost ensure no-one in a group shot has their eyes closed, by Nic Svenson and Piers Barnes

Ornithology: Why woodpeckers do not get headaches, by Ivan Schwab and the late Philip RA May (see photo)

Nutrition: Why dung beetles are fussy eaters, by Wasmia al-Houty and Faten al-Mussalam

Acoustics: Why the sound of fingernails scraping on blackboards is so annoying, by D Lynn Halpern, Randolph Blake and James Hillenbrand

Medicine: The Termination of Intractable Hiccups with Digital Rectal Massage, by Francis Fesmire, Majed Odeh, Harry Bassan and Arie Oliven.

Friday, November 3, 2006

Can you swim faster in water or syrup?

It's a question that has taxed generations of the finest minds in physics: do humans swim slower in syrup than in water? And since you ask, the answer's no.

Scientists have filled a swimming pool with a syrupy mixture and proved it."What appealed was the bizarreness of the idea," says Edward Cussler of the University of Minnesota, Minneapolis, who led the experiment.

It's a question that also fascinated his student Brian Gettelfinger, a competitive swimmer who narrowly missed out on a place at this summer's Olympic Games in Athens.Cussler and Gettelfinger took more than 300 kilograms of guar gum, an edible thickening agent found in salad dressings, ice cream and shampoo, and dumped it into a 25-metre swimming pool, creating a gloopy liquid twice as thick as water.

"It looked like snot," says Cussler.

The pair then asked 16 volunteers, a mix of both competitive and recreational swimmers, to swim in a regular pool and in the guar syrup. Whatever strokes they used, the swimmers' times differed by no more than 4%, with neither water nor syrup producing consistently faster times, the researchers report in the American Institute of Chemical Engineers Journal 1.

Planning permission

The most troublesome part of the experiment was getting permission to do it in the first place. Cussler and Gettelfinger had to obtain 22 separate kinds of approval, including persuading the local authorities that it was okay to put their syrup down the drain afterwards.But it was worth the hassle, Cussler says, not least because his quest for an answer made him something of a celebrity on campus. "The whole university was arguing about it," he recalls. "It was absolutely hilarious."But while it might sound like a trivial question, the principle is actually fundamental.

Isaac Newton and his contemporary Christiaan Huygens argued the toss over it back in the 17th century while Newton was writing his Principia Mathematica, which sets out many of the laws of physics. Newton thought that an object's speed through a fluid would depend on its viscosity, whereas Huygens thought it would not. In the end, Newton included both versions in his text.Hamstrung by their lack of access to guar gum or competitive swimmers, Newton's and Huygens' work was mainly theoretical. Cussler's demonstration shows that Huygens was right, at least for human-sized projectiles.

The reason, explains Cussler, is that while you experience more "viscous drag" (basically friction from your movement through the fluid) as the water gets thicker, you generate more forwards force from every stroke. The two effects cancel each other out.

That's not always the case. Below a certain threshold of speed and size, viscous drag becomes the dominant force, making gloopy fluids are more difficult to swim through. Had Cussler done his experiment on swimming bacteria instead of humans, he would have recorded much slower times in syrup than in water.

But for humans, speed depends not on what you swim in, but on what shape you are. Once the effects on thrust and friction have been cancelled out, the predominant force that remains is 'form drag'. This is due to the frontal area presented by a body - try running with a large newspaper held in front of you and see how much more difficult it is.

So the perfect swimmer, whether in water or syrup, has powerful muscles but a narrow frontal profile.

"The best swimmer should have the body of a snake and the arms of a gorilla," recommends Cussler.

The journal that published the study is the American Institute of Chemical Engineers Journal, not the American Institute of Chemistry and Engineering Journal as initially reported.

Wednesday, November 1, 2006

Scientists, writers and the Archbishop of Canterbury reveal their favourite science books

Jim Al-Khalili, theoretical physicist, University of Surrey
I have given this some thought and it is a toss-up between two books.

The first is Dan Dennett's Consciousness Explained. As a physicist I enjoy reading about something I do not know much about. Dennett's book really opened up a whole new world for me. His rational, mechanistic and reductionist view of consciousness and how it manifests itself was a revelation. It is most likely not the whole answer, particularly in the light of research over the past decade or so in AI, cognitive studies and neuroscience. But I found it incredibly convincing and enlightening.

The second is Roger Penrose's Shadows of the mind. This was Penrose's first popular science book and sparked worldwide interest linking many ideas in quantum mechanics, the nature of time, artificial intelligence and the root of consciousness. I did not, and do not, agree with Penrose's main thesis on the quantum origins of consciousness in the brain. But there was so much more to this book, on non-computability, the meaning of quantum mechanics and its connection to other fields of physics that it profoundly affected my thinking.

If I had to choose, I would go for Dennett though.

Philip Ball, author

I'd like to suggest two candidates. The first is a widely recognized classic: D'Arcy Wentworth Thompson's On Growth and Form, first published in 1917 and then in revised and expanded form in 1942 (that version is available as a Dover reprint, 1992). Not all of the science in this book is accurate, and some is wrong. Much of it has been superseded, and in fact Thompson was writing well ahead of his time, before the tools and concepts were really developed to tackle many of the problems he considered. All the same, it is a great book. For one thing, it challenges the notion, still apparent today, that somehow biology escapes the constraints that apply to the rest of the physical world: Thompson was refuting the tendency in his time to explain all biological form with the black box of Darwinism. It shows the value of taking a synthetic view that cuts across scientific disciplines. In short, it provides nothing less than a new way of looking at the natural world. And it is written beautifully and with stunning erudition.

The second is barely known: Norbert Wiener's Invention (written in the 1950s but not published until 1994 by MIT Press). Wiener is best known for cybernetics, but here he makes an elegant case for the importance of the often overlooked creative strand of science evident in the process of invention. He explains how invention can be, and has been, nurtured, and what can go wrong in an intellectual climate to suppress it. To my mind, this book shows why the claim that science is somehow different from technology is not just wrong but pernicious.

Susan Blackmore, psychologist, writer and broadcaster
I tried to think up something original or quirky but in the end I have to say my favourite is The Selfish Gene. It taught me, in beautiful language, the simplicity and power of Darwin's dangerous idea - "the best idea anybody ever had" and inspired all my subsequent work on memes.

David Deutsch, physicist, University of Oxford
I'm afraid I find it impossible to choose between Gödel, Escher, Bach and The Selfish Gene. Both are examples of perfection in popular science writing: they deal with issues that are deep and important, but subtle enough that they are usually only discussed by specialists, and they make them accessible to the general reader through the authors' superlative writing skill and total command of their subjects.

K Eric Drexler, nanotechnology pioneer, researcher and author
Mathematics, Form and Function by Saunders Mac Lane. Written by a pioneer of category theory, which links parallel structures across all areas of mathematics, this book provides a survey and integration of mathematics as a whole. It both shows the roots of mathematics in concrete human experience and explores the content of fields at the heights of abstraction, emphasizing their surprising connections. This is a book to be skimmed, then read, then revisited and studied.

Marcus du Sautoy, Professor of Mathematics, University of Oxford
Hardy's A Mathematician's Apology is a book I was recommended by teacher at school to read when I was 12 or 13. It was a revelation. It brought alive what mathematics is really about. It was like hearing real music for the first time after practising scales and arpeggios for years. I think everyone has a sense of what the chemist, physicist or biologist is investigating in their laboratories but giving someone access to the mathematician's lab is a much tougher job. Hardy shows that mathematics is as much a creative art as a useful science and that really appealed to someone who loved music as much as numbers. He gives two proofs in the book: they are simple but rapier-like in their logic. Being exposed to the power of this logical language to prove things with 100% certainty was very empowering to an adolescent whose world was constantly shifting.

As an adult it is a book I love and hate because it comes with a very mixed message. Anyone who wants to emulate Hardy and bring the subject alive for others lives under the spectre of the opening sentence of the book:
“It is a melancholy experience for a professional mathematician to find himself writing about mathematics. The function of a mathematician is to do something, to prove new theorems, to add to mathematics, and not to talk about what he or other mathematicians have done.”
I have spent my adult life trying to prove Hardy wrong: that it is possible to create new mathematics alongside providing access for others to this magical world.

Richard Fortey, senior paleontologist, Natural History Museum
I would like to nominate Oliver Sacks' book The Man who Mistook his Wife for a Hat. Sacks manages to explain much about how the human brain works, but in a way which is absolutely gripping as literature. He avoids the pitfalls of becoming too precious - everything is perfectly judged. He also has the prize for the most intriguing title - out Goulding Gould!

Baroness Susan Greenfield, Director of the Royal Institution

How to Build a Time Machine, by Paul Davies. Hugely original in terms of format. It looks easy – like a picture book – but introduces you to lots of difficult concepts.

Steve Jones, Professor of Genetics, University College London
To me one obvious winner - Charles Darwin's The Voyage of the Beagle. No other book so conveys the excitement of doing science, getting results and having a wonderful time, all at the same time. And, as well as a great science book, it's one of the best travel books ever written, with more adventures on a single page than most modern writers manage to squeeze into a chapter, or an entire book.

Marek Kohn, author
Mason & Dixon, by Thomas Pynchon. ‘”The mists rise up out of the Bog. There she is, full, spherickal ... the last time I shall see her as a Material Being ... when next appearing, she will have resum'd her Deity.” Maskelyne will edit this out, which is why Mason leaves it in his Field Report.’ Thus Pynchon imagines the eighteenth-century astronomer Charles Mason observing a Transit of Venus: subtle phrasing, prose that sustains lasting pleasure, mischief, irony and wit; powerfully imparting a sense of science in a world still haunted and occult, and reminding the reader of all that is absent from conventional science writing.

Tim Lott, author
My favourite science book is The Blank Slate by Stephen Pinker. It really opened my eyes to a huge number of ways in the way the general public and the media misperceive the nature of human nature, out of a misplaced need for control over the human personality. Pinker's remarkable book re-establishes inborn human nature as being at the heart of the personality, and does it without in any way handing the baton over to determinism, or ignoring the importance of environmental factors. I have read and re-read this book, and it has changed the way I think not only about the human mind, but how society allows it wishes to impinge on its ability to judge matters of science on the evidence available. A brave, groundbreaking victory for both common sense and free speech, The Blank Slate forces us to look at many of the deepest assumptions that our society holds and makes us start to radically revise them.

Mark Miodownik, lecturer in Mechanical Engineering, King’s College London submitted a list that included The Hitchhiker’s Guide to the Galaxy
My main problem, I have come to realise, is that I read The Selfish Gene and Day of the Triffids too early and so became both paranoid and solipsistic at far too tender an age. While other children were laughing heartily at Terry Pratchett's bonkers prose or smiling tenderly at A Wrinkle in Time, I was pondering the implications of A Brief History of Time and trying to understand why the publishers ever went ahead with it. When I finally got round to reading the The Hitchhiker's Guide to the Galaxy, I was a shocked and serious teenager, and I found the book so much funnier and cleverer than any other book I had read that I wore my dressing gown to school for a week, and would frequently burst into hysterical laughter at the mere mention of the word 'petunia'.

Toby Murcott, science writer
My book would be Surely You’re Joking, Mr Feynman. Richard Feynman gives the best insight into genius that I have ever read. He constantly baffles and amazes people by doing the obvious. His particular genius is to see the world with childlike eyes, ignore his beliefs and prejudices and just take problems at face value.

Vivienne Parry, writer and broadcaster
My favourite science book by a mile is The Voyage of the Beagle. It sits by my bed and I often dip into it. In fact I've just had to replace it for the 3rd time as it has been loved to death and fallen apart. It's a book written by an enthusiast who noted everything around him, plants, animals, rocks and people. It works as a terrific travel book, as a riveting insight into the scientific journey of one of the world's great scientists and as a great read. What more could you want?

Steven Pinker, Professor of Psychology, Havard University
Thomas Schelling, The Strategy of Conflict, 1960. A masterpiece by a humane Dr. Strangelove, recent winner of the Nobel Prize in economics. This book introduced dozens of mind-blowing ideas on culture, emotion, conflict, cooperation, communication, and social life, whose full implications we are only beginning to explore. It is packed with wit and insight, and uses mathematical game theory judiciously. Malcolm Gladwell's The Tipping Point and Robert Frank's Passions within Reason, both excellent bestsellers, were based on Schelling's ideas.

Matt Ridley, author
The Selfish Gene by Richard Dawkins. I still recall a sense of slight bewilderment when I read the newly published book as a first-term undergraduate at Oxford. Was this chap’s theory right or not? Until now my teachers had helpfully divided the world of science into right and wrong ideas. But here, I suddenly realised, I was going to have to make up my own mind. The handrails had gone. Dawkins’s sentences had such rhythm, his words had such precision and his thoughts had such order that his book was tasty literature as well as nourishing argument.

Dr Rowan Williams, Archbishop of Canterbury
Oliver Sacks, A Leg to Stand On, 1984. Challenges all sorts of assumptions about mind and body, and sketches a very exciting concept of the body itself as ‘taking shape’ in mind and imagination.

Heinz Wolff, former Head of the European Manned Space Commission
My entry for the best science book ever is of course a very personal choice. The Microbe Hunters by Paul de Kruif, published first in 1926, did more to inspire me into science and medicine, than anything else I have read since. It has been republished quite frequently and can be bought readily in various formats from Amazon.

Tuesday, October 31, 2006

Dare you enter the haunted house?

click the picture to play the spooky game!!!!!!

Do you believe in ghosts?

Warning: this is very scary - make sure you are not alone and you have turned on your speakers - do not get too close to the computer screen - you must read all the stories carefully before you click to the next slide (Click here to proceed!!)

Saturday, October 28, 2006

Female Scientists















Know any girls who might be wondering what it’s like to study physics at uni? They can find out (for free) by signing up to Planet Jemma. Watch daily video diaries about Jemma’s life and receive regular emails written especially for you. Be inspired by very cool women scientists!

Screaming Cups

You've never heard a sound effect quite like this coming out of an ordinary cup!

You will need:

Fishing line or smooth string (it's worth trying a few different types to find what works best)
A plastic cup (yoghurt pots work too)
A damp cloth
Tape or modelling clay

What to do:

Cut a length of string about the height of the cup.
Stick the string to the centre of the inside of the cup with the tape or the clay.
Turn the cup upside-down. The string should hang down inside the cup.
Draw the damp cloth along the length of the string; this starts the string vibrating as the cloth slips and sticks - which is just how a violin bow works.
What in the name of tarnation is that hideous row? Is someone killing a chicken?

What’s going on?

Vibrating a piece of string in the same way with a damp cloth produces a sound, but it's very quiet. Adding the cup to the end of the string creates a larger surface to vibrate, amplifying the sound.


Want more?

You can do exactly the same as above, but on a bigger scale, with a bucket. Or better, use a variety of differently sized buckets, with bowls and cups and even bins. If you can get a really giant bin (half a metre in diameter) you get a really deep noise that sounds more like a cow than a chicken!

Look for this and many more cool experiments you can try at home in the Little Book of Experiments (click to open)

Friday, October 20, 2006

Today's lesson!

Just because half term has started does not mean we cannot teach you! Here is a series of excellent mini lessons (with some questions to see how well you have understood). This lesson supports the year 10 chemistry topic C2 Classifying the Elements, but no matter what year you are in you should learn something from it. Note: turn on your speakers & flash player required. Look out for more lessons in the future or email me with topics that you need help with and I will try my best to find some lessons for you!

Click on the image below to load the lesson.

Monday, October 16, 2006

Green pennies

You will need:

A saucer
Some paper towels
Vinegar
3-5 pennies

What to do:

Arrange the paper towels into a wad on your saucer.
Pour enough vinegar into the saucer to cover the paper towel.
Place the pennies on top of the wet paper towel and leave for a few hours.
Encourage observations; look at both sides of the pennies. The tops of the pennies turn green and the bottoms of the pennies stay copper coloured.

What’s going on?

Vinegar is an acid that has the chemical name of 'acetic acid'. Part of this acid combines with the copper of the pennies to form a green coating that is composed of copper acetate. Oxygen must be present for this chemical reaction to occur. Oxygen comes from the air, and this is why the tops of the coins turn green but the bottoms do not.

Wednesday, October 11, 2006

You simply have to applaud creativity........

"A short video me and friend just finished for thefirstpost.co.uk . It took about 2 weeks to plan and animate and was made entirely with a digital stills camera."

Rocket Physics - don't try this at home!


Sunday, October 8, 2006

Thursday, October 5, 2006

Play with a DNA copying machine

PCR is a method by which a few fragments of DNA can be duplicated into millions in a couple of hours. This makes PCR a very useful method in forensic science, as it means that very small amounts of DNA could be enough to identify a person. PCR was invented by Kary Mullis, one of two Nobel Laureates in Chemistry in 1993. If you play the game below, you will be able to learn more about PCR. Also, a must for HL Biology and Chemistry students is the 30 min lecture by Roger D. Kornberg, the winner of the 2006 Nobel Prize for Chemistry for his studies of the molecular basis of eukaryotic transcription.

Click here to play the DNA game

Click here for the lecture (real player required)

Click here for an interview with Roger D. Kornberg after he won the prize

Click here visit the Nobel Prize home page to see who won the other awards

CLick here to play some other games related to the Nobel Prizes

Wednesday, October 4, 2006

Spinning Juice

Finished your drink of juice? Great! No don’t throw away the empty carton! Here’s something fascinating….

Adult supervision required.

You will need:

empty 1 litre fruit juice carton
piece of string
pair of scissors
washing up bowl
water

What to do:

Poke a hole in the bottom left hand corner of each of the four faces of a 1 litre juice carton. (children should be helped with this bit by adults)
Poke an extra hole in the top flap of the carton and tie a string through it.
Hang the carton from the string.
Pour some water into the washing up bowl so that it is about one quarter full.
Place the carton into the bowl of water.
Pour water into the carton until it is full to the top.
Now lift the carton out of the water by the string and watch what happens!

What’s going on?

Newton's Third Law states that every action has an equal and opposite reaction. Water shoots out the holes, and pushes back on the carton with equal force. A turbine is formed as the energy of the moving liquid is converted into rotational energy. Consequently the carton spins. This effect was first noted by Hero of Alexandria.

Hero (or Heron) of Alexandria (roughly A.D. 10 to roughly A.D. 70) was a Greek engineer and geometer. His most famous invention was the first documented steam engine, the aeolipile. Steam was generated in a separate boiler and fed into a sphere through a hollow spindle. The steam left the sphere via two narrow, angled nozzles and the reaction to the jets of steam leaving these nozzles made the sphere spin.

To see an animation of Hero’s Aeolipile click here.

Tuesday, October 3, 2006

So pigs can fly - here's the evidence!!

Watch this amazing dragon follow your eyes

Results for the snack card challenge will be posted shortly. Meanwhile enjoy this strange dragon optical illusion. Whatever next? Flying pigs?

Wednesday, September 27, 2006

This obeys the laws of Physics, but still unbelievable!

Ok - when was the last snack card challenge? Too long ago I hear you say. Well this one is a little more challenging than most. Can you calculate the velocity this Japanese guy needs to cover the 6.30m to break the world record? (hint: time of flight). Post your answers below (first name and tutor group). Correct answer wins a 100B snack card.

Monday, September 25, 2006

Sylvester and Tweety

Watch this until Sylvester catches Tweety... wait for it, it's worth it.
After Tweety is caught, scroll down.






















That was an idiot test. How long did you watch?
0-2 sec - There's hope for you.
2-5 sec - Having a bad day?
5-10 sec - Are you maybe just a slow reader?
10-20 sec - Should you be at this school?
20 - 30 sec - It is recommended that you don't have children.
30 sec - 1 min - You are somewhat low down in the food chain.
1 - 2 min - The equivalent of the average house plant.
2 - 5 min - Good afternoon Jessica Simpson.
5 min -1 hr - Dead people score in this range.
1hr plus - Congratulations. You have a negative IQ.

Sorry ;)

Saturday, September 23, 2006

More optical illusions!

Sunday, September 17, 2006

How far can you swing?


WARNING: this game is highly addictive! No school so try this challenge - see if you can beat 453m (my top distance) - post yours as a comment below!

Optical illusion

This is powerful .................


click play in the bottom left of the slide (turn on your speakers)

Thursday, September 14, 2006

How much weight can a bridge take?














Year 10 students find out in their Physics classes.

Wednesday, September 13, 2006

Sunday, September 10, 2006

Bubble Painting

You will need:

•Paper
•Containers with wide tops (e.g. plastic cups, yoghurt pots)
•Powder or liquid paint
•Washing-up liquid
•Straws

What to do:

1.Put a squirt of paint and a squirt of washing-up liquid into one of the containers.
2.Add a little water and mix well until the mixture is runny enough to blow bubbles with.
3.Using the straw, blow into the mixture (Okay Mr Bluechops - who sucked instead of blowing?) until the container is so full of bubbles that they rise above the top rim.
4.Quickly take a piece of paper and lightly touch it onto the bubbles. As they touch the paper, the bubbles will burst. You will be left with a lovely pattern of circles. Leave to dry then build up layers of colour.

What’s going on?

Surface tension of water makes it impossible to stretch out to create a thin film or bubble on its own. There is a strong attraction between water molecules, preventing them from being stretched thinly enough to produce a bubble. However by adding soap to water, the soap reduces the surface tension and allows bubbles to form.
A soap film always pulls in as tightly as it can, just like a stretched balloon. A soap film makes the smallest possible surface area for the volume it contains. Most bubbles are spheres because it is the shape that has the smallest surface area compared to its volume.

How far would an air particle travel in a soap bubble in 1 second?

Imagine the air in a small soap bubble, about the size of the tip of your little finger. All those little molecules dashing about bumping into each other.

Watch the bubble for one second. Each molecule does a crazy zig-zag journey, colliding with other molecules and bouncing off the sides of the bubble. Suppose that you could measure the length of each of these journeys, and add them up. What do you think they would come to?

What is the total distance travelled by the air molecules inside a small bubble in one second? A hundred metres? A hundred kilometres? A thousand kilometres?

The actual answer is...one million light-years!
You don’t believe me? Read on...

To work out the total distance, we need to multiply the average speed of the air molecules by the number of molecules inside the bubble.

Physics textbooks tell us that the average speed is roughly 500 metres per second.

To work out how many molecules are in the bubble, start with the fact that one mole of a perfect gas occupies 22,400 cubic centimetres at everyday temperature and pressure.

Our bubble contains about one cubic centimetre of air, so there are 1/22,400 moles of gas in there.

Now one mole of anything contains 6 x 10^23 molecules (Avogadro’s number).

So the number of molecules in the bubble is 6 x 10^23 divided by 22,400, which comes to about 2.5 x 10^19 molecules.

And if each molecule travels 500 metres in one second, the total distance travelled is about 10^22 metres.

As a light year is about 10^16 metres, this means that the total distance travelled in one second by the molecules in the bubble is 10^6 (a million) light years.

What this result brings home is not the speed of the molecules – Concorde flew faster – but just how many of the little blighters there really are.

Friday, September 8, 2006

Sunday, September 3, 2006

Thursday, August 31, 2006

Straw Oboe

This is a noisy, amusing demonstration of the physics of music. It can take a bit of practice to get exactly right, but it's well worth the effort.

You will need:

straws (need to be straight – cut off the bendy bits if there are any)
scissors

What to do:

Flatten one end of the straw ~2cm from the end to the tip.
Make two cuts in the now flattened end of the straw, to form a triangular tip.
Insert the triangular tip of the straw into your mouth and blow hard. You should hear a loud 'buzzing' sound.
While blowing on the straw oboe, get a volunteer to cut the straw shorter, ~1cm at a time. With each cut you will hear the pitch of the oboe sound go up.

What's going on?

The flattened triangular tip acts like the reed found in most wind instruments. Blowing on the reed causes the straw to vibrate. A standing wave pattern is created along the length of the straw, which we hear as sound. As you shorten the straw you shorten the wavelength of the standing wave pattern and therefore increase the pitch of the note.

Note:


It can take some practice to get the right sound – if it doesn't work straight away then slowly move the straw in and out of your mouth whilst still blowing until you hear the sound. Definitely a good demonstration to practice before performing it in front of an audience!

Did You Know?

As long ago as the fifth century BC Pythagoras and his followers were experimenting with standing waves and calculating the values of their harmonics. Another way to set up a standing wave is to blow across the top of a drinks bottle. In this case the note gets deeper as you drink the drink (sorry, tune the instrument).

Egg-straordinary physics tricks

You will need:

raw egg
hard boiled egg

What to do:

Place the two eggs on a flat surface and set them both spinning.
Gently and briefly place your finger on the top centre of each egg.
Notice that the hard boiled egg is much easier to spin, but it stays still when you take your finger off. In contrast, the raw egg is difficult to start spinning but will keep spinning when you take your finger off.

What’s happening?

Momentum is the key to this demonstration. A raw egg is filled with a liquid, whereas a hard boiled egg is effectively a solid. Firstly consider what happens when you stop the eggs: When you gently place your finger on the top, you stop the outer shell of both eggs from moving. Since the hard boiled egg is solid, all of the egg stops moving, and so the egg remains stationary when you remove your finger. However, the liquid inside the raw egg will keep spinning even though the outside shell is stationary. The drag of that liquid on the shell will start the raw egg spinning again. Similarly, a hard boiled egg is easier to spin since the entire egg starts spinning at the same time, whereas in the soft boiled egg only the outer shell is spinning at first, and gradually the liquid insides begin to spin as they are dragged around by the shell.

Tips for Success

Don’t set your eggs spinning too hard or they may roll off the table. Make sure you start them spinning at approximately the same rates or your audience may think you are trying to fool them! As if!

Another egg-sample of physics at work:

Eggs are traditionally thought of as being very fragile, but in fact the physics behind their shape is astounding.

You will need:

raw egg
plastic bag or glove (for the unconfident!)

What to do:

Challenge audience members to break the egg just by squeezing it. Let them wrap the egg in a plastic bag or wear a glove if they're worried… Believe it or not, it can't be done! Shift it Mr Doppler!

What’s happening?

The shape of an egg is actually one of the strongest designs possible. The curved structure means that applying pressure to any particular area actually spreads the force out over the entire egg. So just squeezing it won't cause it to break. Of course applying a very sharp force to one point WILL cause it to break – which is why we usually tap the egg on the side of a bowl to break it when cooking.

Tips for Success

Ask your volunteers to remove any rings etc. before trying this trick – the sharp uneven force from such metal objects can cause the egg to break.

Check your eggs for hairline fractures before attempting this trick – if there is any existing damage to the egg it won't work.

Did You Know?

The ornate and intricate arched doorways and ceilings in many old buildings aren’t just there for their aesthetic qualities. Arches are in fact one of the strongest building structures. In effect, every brick or piece of masonry within the arch is falling on all the others, distributing the weight evenly over the structure.

What happens when you add mentos to coke?

Wednesday, August 30, 2006

Caution: this rocket can fly up to 3-4m. Adult supervision required.

You will need:

Film canister with lid (clear film canisters where the lid presses inside work the best)
Baking powder
Vinegar
Teaspoon
Toilet paper

What to do:

Take the lid off the film canister.
Measure three teaspoons of vinegar into the canister.
Take a sheet of toilet paper and place it on top of the canister.
Press it down to form a small well. Don’t press it down so far that it touches the vinegar! The aim is to keep the two ingredients apart.
Place a teaspoonful of baking powder in the well.
Press the lid on tightly and trim the excess toilet paper from the edges.
Do not turn it over yet and definitely DO NOT SHAKE IT! You don’t want it to go off and hit you in the eye.
Find a clear, safe area outdoors. It is not a good idea to do it where a slumbering dog or nervous cat is in the vicinity. Come to think of it make sure grandma or granddad are not snoozing in the garden either.
Turn the canister over and place it lid-down on the ground then retreat to a safe distance i.e. at least 2m away.
Brace yourself. It will take about 20 seconds or so to launch. The advantage of the clear canister is that you can see the mixture bubbling up. This means that you don’t have to get impatient and approach it just as it shoots up.
Whe-hay! Thar she blows! If you’re lucky it will go over the shed much to the pleasure of any watching kids.

What’s going on?

Vinegar and baking powder react together to form carbon dioxide gas. The gas builds up until it forces the lid off the film canister. The gas pushes downwards which in turn (thanks to Newton and his Third Law) causes the canister to be forced upwards.

Are these forces balanced in a year 8 tug-of-war?

Wednesday, August 16, 2006

Magic Sand

What you need:

Magic sand
Ordinary sand (Hey ho it’s off to the beach we go!)
Teaspoon
Water
Small glasses
Washing up liquid

What you do:

Half fill each glass with water.
Add a couple of teaspoons of ordinary sand to the first glass.
Stir it up and bring a spoonful to the surface. It appears wet. The ordinary sand sinks to the bottom of the pot.
Add a couple of teaspoons of Magic Sand to the second glass.
Some of the Magic Sand sinks to the bottom of the pot. A small amount floats on the surface. Stir it up and bring a spoonful to the surface. It appears dry. The sand that has sunk appears silvery as if it has a coating around it.
See how the sand can be sculpted underwater to form different shapes?
Now add a few drops of washing up liquid to this glass. Stir it up. Can the Magic Sand be sculpted now? What has happened to the silvery layer? If you lift up a spoonful of the sand is it still dry? No it’s not!
Now look at what happens with vegetable oil.
Add two teaspoons of Magic Sand to another empty clean glass. Now add two teaspoons of vegetable oil. See how the vegetable oil soaks into the Magic Sand? Now you can lift out a spoonful of the sand and it no longer appears dry.

What’s going on?

Ordinary sand grains are hydrophilic (water-loving). This is because the surface of ordinary sand contains hydroxyl (OH) groups which are attracted to the OH groups in water molecules.

Magic Sand has been treated with a chemical called trimethylhydroxysilane. After this treatment the surface of the sand contains CH3 groups instead of OH groups. This makes the Magic Sand hydrophobic (water-hating). The Magic Sand repels water and so a layer of air is trapped around the Magic Sand as it sinks. This forms a bubble around the Magic Sand and the silvery layer is caused by the curved surface of the bubble.

Although Magic Sand hates water it loves oil (oleophilic) and so the vegetable oil is absorbed easily and the sand is ‘wet’.

Washing up liquid is a detergent which means that it contains molecules with both a water-hating and a water-loving end. When it is added to the Magic Sand in water it attaches to the water-hating groups on the surface of the sand. The water-loving end is attracted to the water molecules and so the Magic Sand is able to be wetted.

Magic Sand was originally developed as a way to trap oil spilled from oil tankers near the shore. It was developed by chemists at Cabot Corp. with the idea that it could be used to cleanse water of oily contamination. When sprinkled on an oil slick, magic sand attaches to the oil, adds weight, and sinks.

For more experiments with Magic Sand

Magic eh?

Bags of polymer fun

What you need:

A plastic carrier bag.
A pair of scissors.

What you do:

Use the scissors to cut a nick in the carrier bag, between the handles. Try to tear the bag from top to bottom - it's very easy, right?
Now cut a nick in the side, and try to tear it from right to left (or vice-versa). Hard, eh?

What's going on:

Carrier bags are usually made out of polythene, which is a polymer - long chains of carbon atoms. The chains mostly line up, and 'cross- link' to each other.
However, those cross-links are much weaker than the immensely strong bonds along the chains. Thus, while it's easy to separate the chains (tear down the bag), it's harder to split them in two (tear across the bag).
Why, then, are the chains arranged vertically in the bag? Because the chains are much stronger along their length, so the bag can carry a heavier load without stretching.
Most of the time, that works very well. But the designers of carrier bags are nevertheless making a trade-off, since even a small tear in the bag can cause a run, separating the chains. And we all know what happens then.

Monday, August 14, 2006

Build a weather vane

A change in wind direction often indicates an imminent change in the weather. Be prepared for sudden change by making this weather vane. Then sit smugly under your umbrella as everyone else races off the beach in the downpour.

You will need:

a long pin e.g. a map pin
scissors
ruler
glue stick
thin, coloured card
drinking straw
2 pencils with eraser
compass

What to do:

Make a sandcastle. Alternatively if you’re not on the beach you will need to anchor an upturned yoghurt pot firmly.
Make a hole in the centre by inserting the pencil, sharp end first. Make sure that it is firmly in place.
With another pencil and a ruler, draw two large triangles and four small ones on the coloured card. Then cut out the shapes.
Place the small triangles on the base (of the sandcastle or yoghurt pot) as if they were the points of a compass. You may need to weigh them down (pebbles are very handy if you’re at the beach) or stick them to the bottom of the yoghurt pot.
Cut short slits in each end of the straw and insert one large triangle in each end to make an arrow-shaped "vane." Both points of the triangles should be pointing in the same direction.

Push the pin through the centre of the straw and into the eraser on the pencil sticking out of the sandcastle or pot. Make sure the vane swings round easily.
Watch the vane swing in the wind.
Finally, use your compass to determine East, West, North and South, and then label the small triangles accordingly. Now you can tell which direction the weather vane is pointing.
Sit with your back to the wind before eating your picnic!

What's going on?

Weather vanes are one of the oldest of all weather instruments; working by swinging around in the wind to show which direction it is blowing from. Traditionally, weather vanes had a religious importance and appeared in the form of weathercocks on church roofs as early as the 9th Century AD. The head of the cockerel would point into the wind, indicating the direction the wind was blowing from.

The direction in which the vane points indicates the direction from which the wind is blowing. For instance, in a westerly wind, the vane points "West."

The air is nearly always in motion, and this is felt as wind. Two factors are necessary to specify wind, its speed and direction. The direction of wind is expressed as the point of the compass from where the wind is blowing. Air moving from the north-east to the south-west is called a north-east wind. It may also be expressed in degrees from true north. A north-east wind would be 45°. A south-west wind would be 235°.

For more interesting facts about the wind
http://www.weatherwizkids.com/wind1.htm and
http://www.rcn27.dial.pipex.com/cloudsrus/wind.html

For more details of how to measure the wind
http://www.rcn27.dial.pipex.com/cloudsrus/measurewind.html

And if that has whetted your appetite for the weather then checkout
http://www.weather-climate.org.uk/05.php

Sunday, July 30, 2006

Bioscience Photography Competition and 3D photos

The Centre for Bioscience at The Higher Education Academy, University of Leeds, are launching a photographic competition on the theme of 'Bioscience in Action' where they are asking for entries from non-professional photographers on any angle of bioscience, including teaching it. The prizes are £500, £200 and £100 for first, second and third winners. There’s a few rules and regs, those and the entry forms etc. are all on their webpage here.

Imagine if instead of looking at photographs, you could walk through them. How amazing would that be? That's what a new computer programme may enable people to be able to do, and it could be ready in 2006.

The software firm Microsoft has come up with a way of matching up different images of a particular subject and then collecting them together in one virtual 3D model. A computer user could then walk or fly through the scene to look at any of the pics from any angle. Wow!

The technology is expected to be available online. People could upload their photos to a website, and then combined with other images, could produce a 3D model. The technology, called Photosynth, could also be used in tourism, with visitors able to take a virtual tour of some kind to see if they like the look of a place before they go. Right let’s have a look at the latest rides at Alton Towers.

It sounds a bit like the Magic Eye pictures that were so popular in the 1990’s. These were also known as 3D stereograms. People used to stare blankly at an image of coloured dots and swirly things, crossing and uncrossing their eyes, saying “I think I can see it – is it a goat on a skateboard?” Actually no, it’s supposed to be someone’s corporate logo. So you see the problem, not everyone can do it. Also you need vision in both eyes to do it. So no chance for Nelson then or poor old King Harold.

The grandfather of 3D art and stereographical headache is Charles Wheatstone. In 1833 he accidentally discovered that because human eyes are set a short distance apart, images viewed through one eye differ slightly from the other. This creates an illusion of depth. Five years later, he invented the stereoscope. This is a binocular device through which a pair of monocular images are projected to both eyes. The optic axes converge at the same angle, thus giving the impression of a solid 3D image. Say that again in English. No on second thoughts don’t bother. Basically the brain can be fooled into thinking it’s seeing something it’s not. Optical illusions eh?

Test your logic - can you think outside the box?
























Remember - you are only allowed 1 minute!
Scroll down for the answers
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How well did you score? Comments welcome!

Have you ever wondered how those vending machines worked?

Thursday, July 6, 2006

What is this pic?

Hints:
•I was discovered in 1976
•I was the subject of a 2000 movie starring Gary Sinise
•I was once believed to be evidence of alien life

Answer:
The original Mars face caused a sensation when images of a face-like hill produced by Viking 1 in 1976 were published across the world. The face, along with nearby pyramid-like structures, was believed by some to be an artificial structure constructed by alien life as a message to Earth. It was made the subject of a movie; Mission to Mars in 2000. The structure is a flat-topped hill, called a mesa, in which different rock types have eroded at different rates to produce the features of the face. Nice try with Keith Richards!

The world's smallest football pitch!

A German scientist has used nanotechnology to create what he believes is the world's smallest soccer pitch.

Dr Stefan Trellenkamp, from the University of Kaiserslautern, made the pitch by using an electron beam to engrave lines onto a tiny piece of acrylic glass.

The pitch measures 380 by 500 nanometres and can only be seen through an electron microscope.

"I am really, really proud," the nanotechnology researcher says.

"The only problem is that I really don't know what to do with it. I can't put it on show as no one can see it," he says. "I guess it'll just stay in my drawer for the time being."

Trellenkamp says it took him a whole day to etch the pitch, which is so small that 20,000 of them could fit onto the tip of a human hair.

Saturday, July 1, 2006

Tuesday, June 27, 2006

Strange optical illusions

Concentrate on the cross in the middle, after a while you will notice that this moving purple dot will turn green! Look at the cross a bit longer and you‘ll notice that all dots except the green one will disappear. More mind bending illusions can be found on this powerpoint (right click, file save as) and this website. Enjoy!

Ever wondered who was bigger – King Kong or Godzilla? Well, you’re still not really going to find out, but it's one of 20 interesting questions you'll find about your senses on the BBC website’s Senses Challenge. Have a go, see what you think…and find out what goes with white chocolate, broccoli, caviar or bacon? Eww, just the chocolate please. I got 12/20 - post a comment about how many you got!




Sunday, June 25, 2006

Wave Machine

What you need

A roll of gaffer tape. Duck or Elephant brands are the best. Which is a shame, since they're twice the price of the others, but so it goes.
Lots of wooden kebab skewers.
More fruit pastilles than seems reasonable.
Two tables or chairs of the same height.
a ruler, or a number of fingers that are approximately the same width as a ruler.

What you do

Stretch the gaffer tape between the furniture. It's probably best to try this with a 2 metre span the first time, but I've done spans of up to 4 metres with some success. You need to stretch the tape taut, which means sticking it down firmly - go right round the table or chair if you can. Mind that varnish!
Starting from one end, stick kebab skewers to the tape so they stick out evenly on either side. This is why you need good-quality tape - you'll need strong adhesive to hold the skewer. A damp day will ruin the adhesive, too - if your skewers fall off, this could be why.
Space the skewers about a ruler's-width apart. The exact spacing isn't critical, so long as they're fairly evenly-spread. Keep adding skewers until you've reached the end of the tape.
Now put a fruit pastille on each end of each skewer. You might think you'd only need twice as many sweets as you've used skewers, but mysteriously they tend to disappear. Further experimentation is required to ascertain precisely why. Much more experimentation. Way more, in fact.
However, be careful when pushing the sweets onto the skewers. Careful in case you accidentally poke your finger, but also because you want the skewer to stay balanced - it should rest horizontally. You may need to push things around a bit to make sure your wave machine stays balanced all along its length.
Once that's done, your wave machine is ready. Hold the skewer at one end, swiftly pulse it up and down, then let go. You should see the pulse travel the length of your tape, reflect off the far end, and return to the start. If you drive the end continuously, you can set up a standing transverse wave, too.

What's going on

Transverse wave machines like this have been around for years, but they're normally very expensive. Not only does this version cost far less, it often works better too!

The tape acts as a torsion spring, but - and this is key - one with a very low spring constant, and very low damping. The fruit pastilles and kebab skewers provide a high angular momentum, too. The result is a wave that travels down the tape at a surprisingly slow speed, as the tape struggles to return to its central position.

With a little practice, you can demonstrate not just standing waves, but things like wavepacket dispersion too. Now that's something you didn't expect to see done with a fruit pastille, right?

(the photo, by the way, is of an early prototype of this demo. It works quite well with elastic, as you see here, but the gaffer tape version is simpler, more reliable, cheaper, looks better, and is easier to set up)

How round is your planet?

When is a planet not a planet? That is the question. At least according to the International Astronomical Union (IAU). For the first time, the organisation will be officially defining the word "planet", and it is causing much debate in the world of astronomy. There is only one thing that everyone seems to agree on: there are no longer nine planets in the Solar System.
The whole debate was sparked off by the discovery in January of last year of a potential 10th planet, temporarily named 2003 UB313, which is bigger than Pluto.
Pluto is already an unusual planet. It is made predominantly of ice, and is smaller even than the Earth's Moon.
In 1992, scientists at the University of Hawaii discovered a new collection of objects beyond Neptune called the Kuiper Belt. Some suggest Pluto should no longer be considered a planet, but a Kuiper Belt Object. One researcher has come up with a clear planetary definition he would like to see the IAU adopt. In a nutshell – is it round?
This definition could lead to a Solar System with as many as 20 planets, including Pluto, 2003 UB313, and many objects previously classified as moons or asteroids.
New categories of planet could be introduced. Mercury, Venus, the Earth and Mars would be "rocky planets". The gas-giants Jupiter, Saturn, Uranus and Neptune would be a second category. Pluto, 2003 UB313, and any other objects passing the "roundness test", would be reclassified as a third type of planet - perhaps "icy dwarfs". Whatever the final outcome, by September there will no longer be nine planets in the Solar System. What? What about My Very Easy Method Just Shows Us Nine Planets? How are we supposed to write a rhyme to remember twenty or so planets? There’s no respect…
For more information check out the BBC News website
Pluto - NASA

Thursday, June 22, 2006

Super massive black hole at the centre of our galaxy

Listen Now - 17062006
Download Audio - 17062006

How do you prove that something is there when it can't be seen? Although for
decades the existence of a super massive black hole at the centre of our galaxy
was viewed with scepticism by many astronomers, a team at the University of
California, Los Angeles did the maths to prove it and have taken spectacular
pictures of the galactic centre.

Transcript

You wouldn't think they'd miss a lump the size of a zillion suns lurking down
there in the middle of the galaxy, would you! But it was surprisingly hard to
locate. Professor Andrea Ghez of the University of California, Los Angeles, led
a team who brought it off.

Andrea Ghez: The idea of super massive black holes, black holes that
have a mass of maybe a million to a billion times the mass of our sun wasn't
predicted theoretically, unlike the little black holes that were first thought
of theoretically and then demonstrated observationally. So people didn't believe
that these things could exist, they had no idea how they would form, so why
would there be one at the centre of our galaxy?

Robyn Williams: So how was the argument turned around?

Andrea Ghez: The argument was turned around by doing the experiment to
look for a super massive black hole, and the way we did this was using
principles from freshman physics, measure the masses of a thing by watching how
something orbits around it, just like planets orbiting the sun; you can weigh
the mass of the sun and figure out how small it is. You can actually weigh a
black hole at the centre of our galaxy by watching how stars orbit the centre of
the galaxy. This way you prove that there's a lot of mass inside a very tiny
volume, and that's the proof of a black hole.

Robyn Williams: I suppose, it being black, you can't actually take a
picture of it, can you?

Andrea Ghez: We've seen the plasma around it, and this is a material
that's very hot because it's falling into the black hole, so in that sense you
do have another signature of a black hole by looking at things being heated by,
again, it's the gravity heating things up locally. But from that you can't prove
that it's a black hole but you can look at its dining habits.

Robyn Williams: What it's about it eat. Remind us what a plasma
is.

Andrea Ghez: A plasma is a very hot set of electrons and protons that
are separated from each other, whizzing around.

Robyn Williams: So it's the ingredients of an atom that's not in a
kind of atomic structure, as such, it's just the mash.

Andrea Ghez: Right. Plasma is a gas that's so hot that the electrons
can't stay bound, so they separate out and the atoms aren't whole, you just see
the electrons and the protons and neutrons.

Robyn Williams: So how far away is this plasma soup from the black
hole itself?

Andrea Ghez: The plasma soup is quite close to the black hole. It
extends roughly the size of our solar system. I guess it's a good size to think
of in thinking about the plasma.

Robyn Williams: Well, I would have thought that close enough to be
swallowed ages ago.

Andrea Ghez: It is getting eaten up but it's continually
replenished.

Robyn Williams: How?

Andrea Ghez: From stars that lose their outer shells, that stuff that
falls in towards the centre of the galaxy gets heated up by the black hole and
that's the plasma that you see today.

Robyn Williams: So you're suggesting, in some ways, that the black
hole is characterised by a kind of halo effect of this plasma, and this is what
you might expect to find in other galaxies as well?

Andrea Ghez: Absolutely. Whatever we see in our own galaxy, you expect
to see in other galaxies. Our galaxies are completely garden variety, ordinary
galaxies, so whatever is here must exist in many other galaxies.

Robyn Williams: Why so prosaic? Why can't ours be unique?

Andrea Ghez: Whenever astronomers think that we are unique, we get
ourselves into trouble. I think the general argument is we're probably pretty
typical; our sun is pretty typical and our galaxy is quite common. We see things
that look like our galaxy in outer space.

Robyn Williams: Give me an idea of the ways in which that black hole
may have grown. Was it there more or less in the beginning of the formation of
the galaxy, and has it got bigger? What else has happened to it?

Andrea Ghez: There was a large debate just a few years ago; which came
first, the galaxy or the black hole? And today we actually recognise that they
had to form together. We've recognised that there's a connection between the
size of the black hole and the size of the central part of the galaxy, and the
only way that that could exist, that connection, is if they were formed
together. So they came together and they grew together. Black holes get bigger
by swallowing material around it, so they grow throughout their life, and our
galaxy's also growing throughout its life.

Robyn Williams: Is there a limit, like there is in stars, to that sort
of growth? In fact, I think there is a formal limit to the size of stars,
indeed. And is there a point at which a black hole cannot grow anymore?

Andrea Ghez: That's a good question and people are actually posing
that question today, and we don't have evidence but there's certainly theories
that there may be ways in which black holes regulate how large they get, but we
don't know the answer today.

Robyn Williams: We may have many black holes kind of budding off.

Andrea Ghez: Maybe. Or maybe they get so big that they keep things
from falling onto it. In other words, when they get big, they go on a diet.

Robyn Williams: So they repel stuff. I see.

Andrea Ghez: That's one idea. We don't know for sure.

Robyn Williams: What was the paper you published in December?

Andrea Ghez: We published a paper on the first view of the centre of
our galaxy using something called laser guide star adaptive optics. It's new
technology that has allowed us to get the most pristine view of the centre of
the galaxy that we've ever had before.

Robyn Williams: So you can actually, in other words, picture it?

Andrea Ghez: We can picture it. We can make the prettiest picture
you've ever seen. We've had the telescope experience Lasik surgery, so the
pictures that we're obtaining today are much clearer than what we could see
before which allows us to see much more detail than what we could see
before.

Robyn Williams: What's it like?

Andrea Ghez: What we see at the centre of the galaxy with these
pictures taken with infrared light, which is just long ward of what your eye
detects, we see light from stars, we see light from the dust that's there, so we
can tell that's it's a fairly hot environment. The pictures that we take, we
take every year, so what we actually see is the stars moving and we see them
moving at incredibly high speeds, which allows us to first discover the black
hole and then to explore whether or not there's any extended halo of dark matter
surrounding the central black hole. There may be an entourage of mini black
holes. That's what we're looking for today.

Robyn Williams: That dark matter is not itself black hole.

Andrea Ghez: Right. So that maybe there's an extended contribution of
dark matter around the black hole itself.

Robyn Williams: Where might people see this picture? Have you put it
on the web or anything like that?

Andrea Ghez: We have a website. If you got to
www.astro.ucla.edu/research/galcenter you'll find our pictures there.

Robyn Williams: That's astro.ucla.edu/research/galcenter to look at
the centre of the Milky Way. Andrea Ghez is professor of physics and astronomy
at the University of California, Los Angeles. And I have no doubt she was a
formidably clever young girl at school.

Guests

Prof Andrea Ghez
Department of Physics & Astronomy
University of California Los Angeles
http://astro.ucla.edu/~ghez/

Further Information

UCLA Galactic Center Group