Stardate Friday 26th August 2005 Issue 147

You will need:

• A plastic bottle of fizzy drink: the stickier it is, the messier it will be to clear up!
• A few raisins
• A drawing pin, pin or needle
• Somewhere outside that can be covered in sticky fizzy drink

What to do:

1. Take the top carefully off the bottle of fizzy drink.  Try not to shake it, so it retains all of its fizz.
2. Carefully make a small hole in the bottle top with the pin.
3. Drop your raisins in and quickly screw the top back on the bottle.
4. Take a large number of steps backwards.

What's going on?

You should now have covered an area with fizzy drink that forced its way out of the hole in the top of the bottle.

Fizzy drinks are made fizzy because they contain carbon dioxide.  An unopened bottle feels hard because the gas is under pressure, forced in during the manufacture.  When you open it, some of the gas escapes.

When you add your raisins, instead of the bubbles just rising to the surface they start to gather around the raisins.  But why so many bubbles?  Bubbles don’t form very well in water as the water tension squashes them and keeps them small.  But the surface of a raisin or other small, rough morsel is perfect for bubbles to form on, partially protected from the water tension, so lots more bubbles are produced.

With all the bubbles forming and rising, the froth builds up.  So with the lid closed the pressure in the bottle increases.  All but the tiny hole in the lid is keeping it all in, and the bubbles of gas and the liquid squeeze out of the top in a sticky shower.

Bubbles are just fab, the way they float, sparkle and create tiny rainbows. But what’s inside a bubble is just as important is its bubble shell…

You will need:

• A plastic bottle or plastic milk carton
• Water
• Washing up liquid
• Baking powder (bicarbonate of soda)
• Vinegar
• 2 bowls

What to do:

Stage One

1. Mix a tablespoon of washing up liquid with two tablespoons of water to make a bubble solution. For super bubbles have a look at the Planet Science bubble recipe, http://www.planet-science.com/text_only/outthere/rss/bubbles.html
2. Turn your plastic bottle upside down and dip the neck in the bubble mixture. When you pull it out check you have a bubble film over the top of the bottle.
3. Squeeze the bottle and watch a bubble grow.
4. If the film pops make another. This time, put the bottle in a bowl of hot water and do not squeeze it. You should get another bubble.

Stage Two

5. Rinse out the inside of your bottle with water and shake it out, then tip in one or two spoons of baking powder. 
6. Get it to stick to the damp bottom and shake out any loose powder.   
7. Add a tablespoon of vinegar to your bubble mixture.
8. Tip the neck of your bottle in again, check for a film, and leave sitting on the table. Watch your latest bubble grow!

What’s going on?

You should have grown three bubbles, all three demonstrating that despite being invisible, air is definitely there!

The first appears because of the displacement of air from inside the bottle when you squeeze it, pushing the air outwards like toothpaste from a tube.

Bubble number three grows because there isn’t enough room for any more gas. The baking powder mixed with the vinegar (which slowly trickles down the inside of the bottle from the neck) forms carbon dioxide. When you add more gas to a container it doesn’t squeeze in happily together with the air that was already in there. Instead, some gas has got to leave – and hence the bubble!

If you are looking for something special to do with the kids this summer we have just the answer for you. Eureka! The Museum for Children is a great hands-on museum especially designed for 0 – 12 year olds. Of course we all know that if it’s great for them it’s going to be fun for parents too!

Step into Eureka!’s new outdoor Maze of Illusions and enter a world of optical magic, where nothing is quite what it seems. With new puzzles and optical effects at every turn, find out how and why your mind plays tricks on you and discover the tricks of depth, distance, light, colour and more as you search for a way out through the Maze’s pathways and dead ends.

The best bit is that the very generous people at Eureka have given us two family tickets to give away. To get into the draw email us at planet-science.news@nesta.org.uk, put ‘EUREKA!’ in the subject and please include your name and address. The draw will take place next Thursday, 25th August at 5pm. 

The Maze is open until 18 September, and is free on entry to Eureka! It’s suitable for children 3 years and up - and adults of all ages! If you are not lucky enough to win tickets, you can find details of opening hours and directions to Eureka! on http://www.eureka.org.uk/

Top athletes can sometimes make their sports look effortless – they might be brilliant but they’d have to try a lot harder without a bit of science. Ian Francis takes us on a tour of the equipment that can turn a great athlete into a sporting star.

In all sports there’s a transfer of energy, changing chemical energy in the muscles to other forms of energy. The most desirable end form is probably going to be kinetic (movement) energy. The more kinetic energy you end up with, the faster you’ll run, the more powerful your tennis serve or the more air gained when slam dunking. Putting more energy in should mean getting more out, but you can also get more out by losing less on the way. This week we take a quick look at one of the ‘half-way energy houses’, what happens to the energy in the middle…

While most of us will not have tried pole vaulting, we’re using a similar energy transfer chain with every step we walk or run. You can even fork out on energy return trainers that claim a more efficient transfer of kinetic energy to potential energy and back to kinetic, with each step. A’level sports science students sometimes do a calculation to work out the actual benefit of these trainers. They reckon it gives a 6 Joule contribution to the bounce in each step, enabling the wearer to jump about 7mm higher, depending on their mass.

So for the time being, those expensive trainers won’t let you challenge the pole vault record without a pole.

Fancy doing some organ transplanting? Luckily no scalpels or sutures are required, and you don’t even need scissors or glue. ICT guru Roger Frost shows us how to get our interactive whiteboards active and put some body parts together.

			Organs of the body In years past we would have students colour in parts of the body, cut them out and glue them together in their books. What fun it was before the days of computers! Today, with no need for glue, you can project the body on the board and drag and drop the bits into place. ‘The Body’ is currently the best of modern cut out activities that now feature 3D organs to position. In several return visits you might also look at muscles, nerves and the skeleton. Lest the pupils feel left out, offer them this alternative body ‘cut out’. Covering similar ground, this second example takes shape as a Word file with a body picture to put together. Again it needs no colouring, no scissors and it uses so much less time for the same result.  The Body - BBC http://www.bbc.co.uk/science/humanbody/body The Body cut-out – Roger Frost www.rogerfrost.com/body

Thanks Roger!

Insight into the invisible Our eyes are pretty handy things, for a start off they tend to stop us walking into things - as long as we use them and pay attention. But it is surprising that our eyes see such a tiny part of the electromagnetic spectrum – just the ‘light’ bit. But what about the rest? This great site gives a bit of insight into what the infrared part of the electromagnetic spectrum looks like. Just as we see different colours, an infrared camera sees different tones of infrared radiation, something we normally perceive as heat.  Guess the object seen in infrared – some are easier and some are harder, but in the end you’ll get a good idea of what a great tool ‘seeing’ in the infrared is. http://coolcosmos.ipac.caltech.edu/ cosmic_games/what/

Green Scene Feel you’d like to do something to reduce your environmental impact? Perhaps you’d like to cut back on your waste, save some energy, and lower your carbon emissions? Planet Science is here to help. Green Scene has info on how to save energy, what happens to your rubbish (just to make you feel a little bit more guilty!) and if you are feeling really inspired – how to be an environmental scientist! Of course, it doesn’t use up that much energy to play a few games of ENERGIZE! http://www.planet-science.com/ outthere/environ/index.html

Thanks for reading, hope you enjoyed it! Please send in your comments and contributions to planet-science.news@nesta.org.uk, particularly if you can do better than these jokes!

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