This guy has mastered the laws of parabolic motion......

Can you bend a steel rod with your throat? Don't try this at home....

What speed is needed to cut down plants?

I did not know ping pong balls were so flammable....

And now the everyday light bulb in slow motion

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.

Co Science B3 Support & Movement - what type of lever is a pig's trotter?

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.

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!

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.

Beat my score of 2235m - there is some science in there - honest!

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:

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.

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.

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.