Solar Eclipse on Wednesday 29th March!

On March 29, 2006, a total solar eclipse will occur when the new moon moves directly between the sun and the earth. The moon’s shadow will fall on the eastern tip of Brazil, speed eastward across the Atlantic, through northern Africa, across the Mediterranean. We will link with The British School of Lome in Togo, West Africa to receive and analyse data they collect on temperature, humidity and light level.

More detailed maps and information of exactly where the shadow will pass can be found on this link and this Nasa site has fantastic multimedia presentations about eclipses.

The IB Physics group at the British School of Lome will be more than welcome to pass on any comments about their experience on eclipse day. They will experience approximately 3.45s of totality, If you have specific questions you want answered you may email Mr Jackson before 06:45 GMT on Wednesday when I can take the questions to the students. At 07:00 we leave for the event. Thailand in on GMT +6.

To see a total solar eclipse, you have to be in exactly the right place at exactly the right time—inside the moon’s shadow as the earth, moon, and sun align.

The second map shows the paths of totality of upcoming total eclipses. To see one in person during the next few years, you may have to do some travelling! The school on Lome will be able to observe the eclipse at 9.15GMT. Watch this space!

The Best Matchstick Trick Ever

What you need:

A matchstick. A cocktail stick will also work, if you fancy a break with tradition
A 10 baht coin
A glass, not much wider than the matchstick (or cocktail stick) is long
A balloon (or a plastic pen, ruler or comb)

What you do:

Stand the coin on its edge, on a handy table.
You need to balance the matchstick (or cocktail stick) on the coin. That could take you a while.
Once you've got everything balanced, turn the glass upside-down and cover the coin and stick with it.
Your challenge now is to get the stick off the coin, without knocking the coin over. You're not allowed to bash the table, touch the glass, or bounce up and down on the floor. (I've slightly given the game away by saying that you need a balloon.)
Blow the balloon up and rub it on your hair/jumper/cat. Now, very carefully, bring the charged side of the balloon up towards the glass. You should see the matchstick start to twitch, and with a deft flick you can tip it off the coin. Alternatively you could use the plastic pen, ruler or comb (but they are not as good as the balloon).

What's going on:

It's another static electricity trick, of course. Rubbing the balloon rubs negatively-charged electrons onto it, so it attracts anything that's positively charged or (more likely) neutral. That includes the glass, coin and matchstick. But the force involved is very small, and only the match is light enough to move.

If you do the trick very slowly, and move the balloon back and forth a little, you should be able to turn the matchstick and control it a little. It looks spookily like there's a length of thread between it and the balloon, but of course there isn't. And you can't be blowing, either - the glass prevents that.

Welcome to the crazy world of animals

This weekend surely has an animal theme. Click here to see how many of these weird and wonderful animals you can identify (thanks to Mrs Moakes). There is a funny animals video on this link and I hear Mr Howes (our Patana swim coach) is thinking of using this Australian technique to improve our “tiger prawns” speed in the pool. Enjoy!

How many people can you fool into thinking you are revising?

Is this your brother? How many people can you fool into thinking you are revising for your science exam? Click the image left to test yourself (flash player needed - turn your speakers on!!) If you also want to practise some paper 1 multiple choice questions then click here and follow the instructions carefully.

Some Good Revision Tips

Andy Darvill says: "This advice is based on my experience of helping students through all kinds of exams. The ideas work for most people, most of the time - but if I've learned anything from life, it's that everybody is different, and that you need to figure out what works for you."

Go to his site on this link to look at top revision tips and use the site to revise. Here are a few others you could try:

BBC Bitesize Revision
Homeworkhigh.com
GCSE Answers
s-cool.co.uk
kent.skoool.co.uk

Search for Orion

The ancient Greeks saw the figure of the Greek myth Orion in the night-time sky. There are several different stories about the birth of Orion. According to one version of the myth, Orion was the son of a poor shepherd called Hyrieus. Once, Zeus, Hermes, and Poseidon stopped by Hyrieus' house. Hyrieus was so generous with his guests that he killed the only animal he had - an ox.

Hyrieus was not aware that his guests were gods. The gods wanted to reward Hyrieus' generosity by granting him a wish. Hyrieus' biggest desire was to have a child. The gods told him to bury the hide of the bull he had sacrificed to them and to pee on it. After nine months, a boy was born in that place. The child became a very handsome and strong man.

He was such a good hunter that he was hired by the king Oenopion to kill the ferocious beasts that were terrifying the habitants of the island Chios. Happy for his success, Orion said he would kill all the wild animals on the earth. But, the earth goddess Gaia, who was the mother of all animals, was not pleased with Orion's intention.

Then, Gaia set an enormous scorpion on Orion. Orion soon realized that his strength and sword were useless against that mighty beast. He tried to escape, but the scorpion stung him to death. As a reward, Gaia placed the scorpion in the sky as a constellation which appears to be constantly chasing after Orion whose figure was also placed among the stars.

Read more about Orion mythology at Windows to the Universe.

The image is courtesy of the United States Naval Observatory Library.

How do you perceive depth?

Depth perception can be upset when rules and knowledge are in conflict, as you can see in these short videos of well-known visual illusions. . This site offers full versions of many scientific papers by Richard Gregory FRS, Emeritus Professor of Neuropsychology at the University of Bristol, especially on perception and visual illusions. The videos are large and can be downloaded in QuickTime or RealVideo formats. If you do not have a suitable player installed on your computer, download one from the links on the page. Enjoy the weekend.

The Whizzing Penny

You will need:

Some UK 1p coins or small washers
A drinking straw
A magnet (even a fridge magnet may do the job)

What to do:

Hold the magnet out in front of your face, and hang a penny from it by its edge. If the penny doesn't stick, you've either got the worst magnet in the world, or a non-magnetic penny. Try another one of whichever seems more likely.
Now take another penny, and hang that from the first one. Join them by their edges, so you're making a chain of pennies dangling from the magnet. Depending on the strength of your magnet, you might be able to make a longer chain; keep going until the last penny only just clings on.
This is where your straw comes in. Very gently, blow through it at the last penny in the chain. Blow to one side, and you should be able to make the coin spin. As it spins faster and faster, you can blow harder and harder, and you should be able to make it whizz around at speeds that must be absolutely terrifying to all penny-kind.

What's going on:

The very last coin in the chain is barely held by the previous one, and they touch only at the tiny spot where their rims meet. As a result, there's only a very small amount of friction acting on the penny when it spins - the most important forces acting on it are you blowing at it, and it having to push the air out of the way so it can spin.

If you think about spinning a coin on a table, there's the same air resistance acting to slow it down, but also lots of friction as it slips and rolls over the tabletop. So the magnetically-suspended coin spins far, far faster, and for much, much longer.

I've no idea how much faster it spins. Three times? Six times? Eighteen times? If your school has a strobe lamp, you might be able to work it out - let me know if you manage it!

True or False? There is no gravity in space

Blame the term "zero-gravity" for this common misconception. Gravity is everywhere, even in space. Astronauts look weightless because they are in continuous freefall towards the Earth, staying aloft because of their horizontal motion. The effect of gravity diminishes with distance, but it never truly goes away. Oh, and while we're at it, it's also untrue that space is a vacuum. There are all kinds of atoms out there, albeit sometimes far apart (and this thin gas adds to the collective gravity budget, too!)IMAGE CREDIT: NASA

Click here to reveal the truth behind more SCIENCE MYTHS listed below:




Adults don't grow new brain cells
Eating a poppy seed bagel mimics opium use
Yawning is "contagious"
A falling cat will always land on its feet
A penny dropped from the top of a tall building could kill a pedestrian
Water drains backwards in the Southern Hemisphere due to the Earth's rotation
Lightning never strikes the same place twice
Humans use only 10 percent of their brains
The Great Wall of China is the only manmade structure visible from space
It takes seven years to digest gum
Hair and fingernails continue growing after death
You get less wet by running in the rain
The five second rule

Hovercraft Mark 2!

Patana's first hovercraft, is now bigger, louder and goes forwards (to a fashion)!
WATCH THE MOVIE

Soap bubbles

Soap bubbles are absolutely beautiful things... for about four seconds. After that, they've drifted off behind the sofa, been eaten by the cat, or impaled themselves on the nearest spider plant. We'd be able to get a much better look at them if only they could be persuaded to stick around a little longer. Well, they can. I came up with this method of viewing bubbles back when I was a student, and every time I've put it on TV I've been reminded of precisely how rubbish a medium TV is. The colours aren't saturated right, the contrast is poor - technically, it's a mess. But in person this is fabulously beautiful. Have a go and see for yourself.

What you need

Bubble mixture. People argue about precise recipes, but frankly – a cup of water with a squirt of washing up liquid in it will work just fine.
Some drinking straws.
A black bin liner
Masking tape
Tracing paper (NB. not greaseproof paper)
A table by a window - preferably a bay window.

What you do

1. Cut a 40cm x 40cm square of bin liner, and tape it to the table – it needs to be absolutely flat and crinkle-free. Dribble a little bubble mixture onto the centre of the bin liner square, and use a straw like a squeegee to spread it out. You need to cover an area about 20cm x 20cm square, thinly and evenly.
2. Now dip another straw in the bubble mix, dot the centre of the bin liner, and, very gently, blow a bubble. Keep blowing until the bubble is about 10cm across, then carefully pull the straw out of the top of the bubble.
3. Half a bubble resting on a black sheet is surprisingly pretty, but there's a further trick to this activity. Roll the tracing paper into a cone shape, as large as you can. You need the narrow end to be large enough for your eye, and the other end to cover the soap bubble - so you may need to tape a few sheets of tracing paper together. Try to keep the seams as neat as you can.
4. By the time that's done your bubble will have burst, so blow another one, and then very gently lower the cone over it. Now look down at the bubble through the cone. How beautiful is that?

What's happening?

The cone does two things. First, it shields the bubble from draughts and falling dust, so it tends to last longer, and the colours settle out more.
Secondly, it diffuses the light source - soap bubbles are best viewed under strong, even illumination from the side, and against a dark background. If your table's a bit dark you can shine a few desk lamps at the sides of your tracing paper, but I took these pictures in the light from a bay window.
As the liquid drains down the side of the bubble, you'll see rings of colour; the colour varies depending on the thickness of the bubble film, and hence how much it refracts light. Eventually - if your bubble lasts long enough - you'll see a central ring that's completely colourless. This is a film so thin, it's not refracting light at all - its thickness is less than the wavelength of the bluest light you can see!
It's called a 'black film,' and if you watch, it'll grow until the entire half-bubble is black. For a brief moment the bubble will be almost invisible - and then it pops.

Jack Frost and the Formation of Crystals

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 is 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.

Your own pet cloud.........

In class today we were looking at the relationship between pressure and temperature. Did you have a go at making the pet cloud for the practical of the week? The science behind the cooling is known as adiabatic temperature effects. Ever pumped up a bicycle tyre? No? But you've eaten soup, right? Let me explain: When you work a bike pump to compress air into the tyre, you might have noticed that the valve gets hot. The valve heats up because you're squashing and squeezing air into a small space (reducing its volume), and that has two effects. It increases the pressure - which is what you want so your tyres don't sag - but it also increases the temperature of the air. The reverse happens when you let air out of the tyre: as the air rushes out it expands, the pressure falls, and you should feel both the jet of air and valve get cold.

How about eating soup? Well, when your soup is too hot, you blow on it, right? But if you just open your mouth and breathe out, the air feels warm (breathe on the back of your hand - it's true!). When you blow on soup, you purse your lips, which has the effect of squirting air out through a nozzle. The resulting jet expands as it leaves your mouth, and as you now know, an expanding gas is a cooling gas. So the jet feels cold. (You can do that on the back of your hand too – there, a science demo that requires no equipment whatsoever.)

The most graphic demonstration of adiabatic effects I've come across was on a TV programme in which some guys took a four-wheeled pedal-powered vehicle and welded a huge water tank to the back of it. The tank was half-full of a quarter of a tonne (250kg) of water, with the other half being full of air... only, the air was pressurised to ten atmospheres.

The idea was that the rider of this contraption would hammer down a racetrack as fast as he could, then pull a handle to open a valve at the back of the tank. The resulting jet of water would thrust him forward like a rocket, quickly doubling his speed.

Astonishingly, it worked, more-or-less. But the valve and nozzle were rubbish, and what with all the sloshing there wasn't a nice clean jet of water - just a spray of water and high-pressure air. Of course, the air expanded and cooled, but not just by a few degrees. Ten atmospheres pressure and an accidentally-rather-good expansion nozzle produced enough cooling effect to freeze water.

They made a rocket vehicle that was propelled not by a jet of water, but by a splatter of ice. It made a heck of a mess, of course, but watching an elderly chap thunder down a track while under ice cube power is quite funny.

Pouring Sideways...

You will need:

a balloon (blown up)
a bin bag or old newspaper. In fact, make that several old newspapers ...
A jar of treacle or pourable honey

What to do:

Cover your table with the bin bag or sheets of newspaper. It wouldn't hurt to cover the floor too. Just in case. Blow the balloon up, and rub it on your hair / something woolly / the cat. With a bit of luck, you'll rub some electrons onto the balloon, and it'll become electrically charged. If you hold the balloon near a gently-running tap, you might just see the stream of water being deflected towards it. Sometimes this works rather well, but even so, it's not terribly exciting. Which is where the treacle comes in ... Hold the treacle jar high above the newspaper, and tip it so a very gentle stream of treacle drizzles out. Now, very carefully, bring the charged balloon near the flowing treacle. Go on, try it. You should see the stream of treacle bending right around the balloon. With a little practice, it's possible to make the treacle flow sideways and even slightly upwards, but you'll need a very steady hand. And yet more sheets of newspaper to catch the drips.

What's going on?

The (negatively-charged) electrons on the balloon attract the (neutral) stream of treacle, just as they attract the water from the tap. However, the treacle-factor has an important effect. Because the treacle is flowing so much slower than water, the force acts for much longer - so the drizzle of treacle bends much more than the dribble of water does.

Popping to perfection

Ever wondered why you get that "crunch" from an unpopped popcorn kernel when you are munching on popcorn at the cinema? It's all down to the chemical change that takes place in the kernel.

The kernels must contain moisture on the inside (a minimum of 14.5% by mass) which will become water vapour when heated, which has a much larger volume and eventually the kernel's outer coating will not be able to contain the pressure build up. That's the pop.

It relies upon the "hull" of the kernel undergoing a chemical change. The cellulose structure changes to become more crystalline when heated, which is great for allowing a high pressure build up inside the kernel (keeps the moisture in, allowing it to expand sufficiently to cause that magic "pop".)

The best poppers have a cellulose that is especially good at turning into crystalline sheets, so that the water is contained inside the kernel when heated, instead of leaking out and leaving just the hard shell for you to crunch on! Read here for the full article.

When were you last bitten by the bug?

Schmidt Sting Pain Index or The Justin O. Schmidt Pain Index was created by Justin O. Schmidt, an entomologist. Having been stung by almost everything, Schmidt created (on his own time) an index to compare the overall pain of insect stings on a four-point scale.

• 1.0 Sweat bee: Light, ephemeral, almost fruity. A tiny spark has singed a single hair on your arm.
  
• 1.2 Fire ant: Sharp, sudden, mildly alarming. Like walking across a shag carpet & reaching for the light switch.
  
• 1.8 Bullhorn acacia ant: A rare, piercing, elevated sort of pain. Someone has fired a staple into your cheek.
  
• 2.0 Bald-faced hornet: Rich, hearty, slightly crunchy. Similar to getting your hand mashed in a revolving door.
  
• 2.0 Yellowjacket: Hot and smoky, almost irreverent. Imagine WC Fields extinguishing a cigar on your tongue.
  
• 3.0 Red harvester ant: Bold and unrelenting. Somebody is using a drill to excavate your ingrown toenail.
  
• 3.0 Paper wasp: Caustic & burning. Distinctly bitter aftertaste. Like spilling a beaker of Hydrochloric acid on a paper cut.
  
• 4.0 Pepsis wasp: Blinding, fierce, shockingly electric. A running hair drier has been dropped into your bubble bath (if you get stung by one you might as well lie down and scream).
  
• 4.0+ Bullet ant: Pure, intense, brilliant pain. Like walking over flaming charcoal with a 3-inch nail in your heel.

See also Scoville scale to measure the hotness of a chile peppers.