SCIENCE ACTIVITY PACK
To celebrate British Science Week, we are proud to present your amazing 8-page Science Activity Pack! With four fantastic home experiments and a fun colouring-in challenge, it’s the perfect way to keep young scientists’ brains buzzing.
8-17 BRITISHMARCH SCIENCE WEEK
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DANCING RAISINS!
See humble raisins in a whole new way, as you make them jump and dance to the music soundtrack of your choice! Follow the simple instructions on the next page to find out how…
MAKE ART WITH MILK
Create beautiful swirling works of art by mixing milk, food colouring and washingup liquid. Once you’ve made your milky masterpiece, read the fascinating scientific explanation to find out how and why the magic happens.
MAGIC ICE SCULPTURES
Make a stream of ‘supercooled’ water instantly transform into a tower of ice – all thanks to the power of science and the wonders of microscopic water molecules.
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OPTICAL ILLUSIONS
From a drawing of a light bulb that magically appears on your wall to a blue circle that mysteriously vanishes, try out these mind-bending optical illusions and discover how what your eyes see can sometimes trick your brain!
COLOURING-IN CHALLENGE
It’s time to get creative with your colouring pens and pencils as you bring this exciting science-themed artwork to life!
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Turnupthevolume – andwatch your dancingraisinsspringtolife. Dancing raisins!
You know all about raisins. They come in a packet from the supermarket, taste sweet and go in porridge. But did you know that raisins grow on vines? Or that the vines they grow on are grape vines? How could that be, you say? Well, here’s the funny thing. Raisins are just dried out, shrivelled up red grapes. This experiment might have been about how to make a raisin. After all, all you need is a grape and a lot of dry sunny days (or some other dry environment). But it isn’t. This experiment is about something far more exciting. You are going to learn to make raisins dance!
Ingredients
● 7.5 g bicarbonate of soda
● 12O ml white vinegar
● A handful of raisins (or sultanas – dried out green grapes – will also work)
● A tall, clear glass
Instructions
1 Put the bicarbonate of soda in the glass.
2 Add the vinegar.
3 Step back and enjoy the show for a minute or so until it calms down a little and looks like sparkling water.
4 Turn on your favourite music (or not – it’s up to you).
5 Add the raisins. Smaller raisins generally work best.
6 Watch them dance! And keep watching. It can take a little while to really get going.
What’s happening?
When bicarbonate of soda mixes with vinegar, a chemical reaction produces the gas carbon dioxide (the same one that makes the bubbles in sparkling water). Gas is lighter than liquid so the bubbles rise. On their way up, some of the bubbles catch in the raisins’ wrinkles and bring them along for the ride. When the bubbles reach the top of the liquid, they pop and join the air above the glass, and so the raisins fall back down and go for another spin.
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M a k e artwith milk…
HOW IT WORKS
Milk is mostly water, but it also contains vitamins, minerals, sugar, proteins, and tiny droplets of fat. You might have heard the expression ‘they’re like oil and water’ used to describe two people who don’t get along. That’s because oil is a kind of fat, and fat molecules (the tiniest bits of fat) and water molecules (the tiniest bits of water) don’t play well together. They can be near one another, but they would never in a million years hold hands. That’s why when you try to wash greasy hands (grease is just fat) with water, the grease doesn’t come off.
So what do you use to get grease off your hands? Soap, of course! That’s because soap is like one of those amazing kids who can be friends with very different people
at the same time.
Imagine that a soap molecule has two hands. One of them is very good at holding hands with water, and the other one is equally good at holding hands with fat. That’s how soap helps the water pull the grease off your hands. When molecules hold hands in this way,
it’s called bonding.
Ingredients
● Milk (whole milk works best)
● A plate or shallow dish
● Food colouring
● Washing-up liquid
● Cotton bud
Instructions
1 Pour enough milk on the plate to completely cover the bottom to the depth of about half a centimetre.
2 Add a drop of each of the four colours of food colouring – red, yellow, green and blue – to the milk. Keep the drops close together in the centre of the plate of milk.
3 Place a drop of washing-up liquid on a cotton bud, then gently touch the centre of the milk with it.
4 What happens?
TOP TIP
Don’t drink this milk. It will taste like soap!
Now back to our experiment. When the soap hits the milk, it instantly starts reaching out its fat-friendly hand to grab the fat molecules floating in the milk. It grabs water molecules with its water-friendly hand, too, but that part is easy because milk is mostly water. When the soap gets near them, fat molecules spin around, finding and bonding with the soap and pushing the water around in the process. That’s what makes the swirls. This would happen even if there was no colouring in
the milk, but the colouring that’s riding on the water helps us see what’s going on more clearly.
As the soap molecules finish pairing up with the fat molecules, the action slows down and eventually stops. Either all of the soap is paired or all of the fat is paired.
Try adding another drop of soap to see if there’s any more movement. If there is, you’ve discovered that there are still more fat molecules that haven’t found a partner at the big colour dance.
Keep adding soap drop by drop until all of the fat has bonded to the soap.
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Here’s a bit of magic you can do in your kitchen using the power of science. With just a few materials, you can make water turn into ice – in an instant! This is made possible by using a process called supercooling, which is to bring a liquid below its freezing point without it actually freezing.
THE SCIENCE BEHIND THE MAGIC
Why does this work? It has to do with the way liquids freeze. Like all other substances on Earth, water
STATES OF MATTER
The diagrams show water molecules in different states. In a gas (vapour) they are far apart. In a solid they fit together.
Ice sculptures!
Make a stream of water instantly turn into a tower of ice – just like magic – all thanks to the power of science…
is made up of atoms. Those atoms are arranged into molecules. When the water is liquid, the molecules move and flow around each other. As the water cools, the molecules move slower. They start to line up into a rigid structure. It takes some time for the molecules to do this. One thing that helps the molecules line up into ice crystals is having an impurity, like a mineral or a speck of dust, to form around. That’s why tap water doesn’t supercool as well as purified water. The other thing that helps the molecules line up is banging or shaking the bottle which, as we’ll see here, causes some of the molecules to run into each other and start forming crystals. This causes a chain reaction, and the rest
of the water freezes quickly. If you leave even purified water in the freezer for longer than 2–3 hours, the molecules will eventually figure it out on their own and the water will freeze.
LIQUID
GAS
SUPERCOOL
a glass
WHAT YOU NEED
bottles of water (purified or distilled water with no minerals is best)
a plate
SOLID/ FROZEN
ice cubes
a grape (frozen) and string (optional)
Right: how your frozen sculptures will look! Continued on next page
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HOW TO DO IT
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Put your bottled water into the freezer for two and a half hours. Make sure not to disturb it.
Top tip
Disturbing the water will cause the ice to form early. Ice may also form if there are too many impurities in the water.
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Shake the bottle or hit it against a table or countertop. You should see the ice crystals form instantly!
Top tip
If your water remains liquid, it has not cooled enough. Put it in the freezer for another 15 minutes and try again.
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When the time is up, carefully remove a bottle from the freezer. It should still be in liquid form. If it is already frozen, check your other bottles. If all have frozen, let them melt and then try again for a slightly shorter time.
Top tip
The time it takes to supercool water will depend on the temperature of your freezer. You can put a bottle of regular tap water alongside your purified bottle. When the tap water freezes, the pure water will be supercooled.
SCULPTING WATER
You can use the other bottles to do other ice magic. Place an ice cube onto a plate. Carefully pour the supercooled water onto the ice cube. A stream of ice will form on top of the ice cube!
AND FOR YOUR NEXT TRICK...
For another fun freezing trick, put a grape in the freezer along with your water. When your water is supercooled, carefully pour it into a glass, and then drop the grape inside or lower it into the water on a piece of string. The ice will instantly start to form around the grape!
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Continued from previous page
Which red dot is bigger?
Look at the red circles in the middle of these patterns. Which is bigger? Amazingly, they are the same size! This illusion is created by your brain comparing the blue circles with the red one. Your perception of how big the red circle is changes depending on the size of the blue circles surrounding it.
The magic light bulb
Stare at the black light bulb for 30 seconds. Now immediately start staring at a blank white wall or a white piece of paper. What do you see? The shape of a glowing white light bulb should magically appear. This illusion is created by your eyes getting used to looking at the black light bulb. When you then look at a white surface, the light receptors in your eyes are briefly overwhelmed by the sharp contrast. This creates a bright white version of the light bulb in your brain called an ‘afterimage’.
Optical illusions and how they trick your brain…
Sometimes we see things that aren’t really there. This is because the brain has to decode the information that it receives from the eyes. When the brain is confused by something, it can change the way we see it in order to make sense of it. Try these amazing optical illusions to experience some of the ways your brain can be fooled!
Compare the grey squares
are in fact exactly the same colour! The shadow cast by the apple fools your brain into making square 2 appear lighter than it really is.
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Compare
the squares labelled 1 and 2. On the left, 2 appears to be a lighter colour. On the right, the grey
line shows that the two squares
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Continued from previous page
The disappearing blue circle
Stare at the red dot for 3O seconds.
What happens? After a while, the blurry blue circle should gradually disappear. This is because your brain gets used to seeing the
blue circle at the edges of what it is focusing on (the red dot). So after a while your brain starts to ignore the blue circle. If you look at the blue circle directly, it reappears!
The vase illusion: what do you see?
What can you see in the picture below?
A black vase? Or two white faces looking at one another? This illusion, sometimes called the Rubin vase illusion after its creator, the Danish psychologist Edgar
Rubin, gives the viewer a choice between two different visual intepretations of the same image. Even if you have noticed both shapes, it is almost impossible to ‘see’ them both at exactly the same moment.
Can you spot the grey dots?
Look at one of the meeting places or intersections where two white lines cross. Smudgy grey dots seem to appear at the other intersections of the white lines, though not at the intersection you are looking at
directly. The contrast between the black squares and white lines fools you into thinking there must be bits of grey in between. When your eyes focus on an intersection directly, they see that nothing is there!
Which of these tables is longer?
The first tabletop (left) appears to be longer than the tabletop below but they are actually identical shapes! Use a sheet of tracing paper to check for yourself. The drawing of the table legs makes them look like 3-D objects. This tricks your brain into thinking that the end of the table at the top must be further away.
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Co l ou r i t i n!
It’s time to get creative with your colouring pens and pencils. Plus, don’t forget to send your science-themed artwork to editor@whatonearth.co.uk. We’d love to see it!
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