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Science Experiments

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Description

Simple experiments for Beaver Scouts:

How can you make a raisin dance?
How can you use salt to make an egg float?
Absorbing Science
Straw through potato
The paralysed finger
Confuse your legs

Demonstrate to Beavers:
Fizzy Explosion Bags
Build a Fizz Inflator
Diet Coke & mentos

Resources

Instructions

How can you make a raisin dance?

You will need:
• Pint size clear plastic cup
• Fizzy pop
• Raisins

Instructions:
Put some raisins into a glass (clear plastic cup) of fizzy pop. Watch the raisins.
How many times do the raisins rise in 30 seconds?

What’s happening?
When lots of air bubbles collect in the wrinkles of the raisins they are lifted upwards. At the top of the cup the bubbles burst, the raisins then sink back to the bottom and it all starts over again.

How can you use salt to make an egg float?

You will need:
• Pint size clear plastic cup
• 1 egg
• Teaspoon
• Salt
• Water

Instructions:
Three quarters fill the cup with water. Carefully place the egg into the bottom of the cup. Ask the Beavers to predict how many teaspoons of salt they think it will take to make the egg float. Beavers take it in turns to add teaspoons of salt, counting as they add. In the name of a fair test the teaspoons of salt should always be the same e.g. a level teaspoon each time. How many does it take before the egg starts to rise?

What’s happening?
The egg will normally sink in tap water, but by adding salt you are changing the density of the water. By changing the water's density you can either make the egg float or submerge. When the egg floats, the water density is more than that of the egg (reason why it floats).

Absorbing Science

You will need:
• Clear container
• Paper towel
• Coloured pens
• Water

Instructions:
Make some dots on the paper towel using the coloured pens in a line about 2 fingers from the bottom of the sheet. Fold the top of the paper towel over the container so the dots are inside the container but not resting on the bottom. Slowly pour some water in until it is just over the bottom of the bottom of the paper towel.

What’s happening?
Watch carefully. The water slowly makes its way up the paper towel towards the dots. Watch what happens when the water reaches the dots…the colour in the dots starts rising! This is because the towel is absorbing the water and taking the ink with it. Eventually the water will make its way through the entire sheet.

Straw Through Potato

You will need:
• Strong straws
• Potato

Instructions:
Watch your leader stab the straw through the potato without bending or breaking the straw. Now you try.
As you hold the potato, keep your fingers on the front and thumb on the back and not on the top and bottom. You don't want to stab yourself! Grab the straw with your writing hand and (shh! this is the secret) cap the top end with your thumb. Hold on firmly to both the straw and the potato and with a quick, sharp stab, drive the straw into and partway out of the narrow end of the spud (not the fatter middle part)

What’s happening?
The secret is inside the straw - it's air! Placing your thumb over the end of the straw traps the air inside. When you trap the air inside the straw, the air molecules compress and give the straw strength, which in turn keeps the sides from bending as you jam the straw through the potato. The trapped, compressed air makes the straw strong enough to cut through the skin, pass through the potato, and exit out the other side. Without your thumb covering the hole, the air is simply pushed out of the straw and the straw crumples and breaks as it hits the hard potato surface.

The Paralysed Finger

Bend your middle finger and place the centre section on a table or hard surface. You will be able to lift your thumb, index, and little finger without moving your middle finger. But it is impossible to lift your ring finger.

What is happening?
The tendons in your fingers are independent from one another apart from the ones in your middle and ring finger. These tendons are connected, so that when your middle finger is folded down you cannot move your ring finger. It feels like your ring finger is stuck!

Confuse Your Legs

Lift your right foot a few inches from the floor and then begin to move it in a clockwise direction. While you're doing this, use a finger your right index finger to draw a number 6 in the air. Your foot will turn in an anticlockwise direction and there's nothing you can do about it!

What is happening?
The left side of your brain, which controls the right side of your body, is responsible for rhythm and timing. The left side of your brain cannot deal with operating two opposite movements at the same time and so it combines them into a single motion. Try this with your right foot and left hand and you should have no problem!

Demonstrate to Beavers:

Fizzy Explosion Bags

Tear a paper towel into a square that measures about 5 inches by 5 inches. Put 1 1/2 tablespoons of baking soda in the centre of the square, then fold the sides of the square in toward the middle, and then the opposite sides in toward the middle, with the baking soda inside. This is your "time-release packet."
Pour into your plastic bag, 1/2 cup of vinegar and 1/4 cup of warm water.
You need to drop the time-release packet into the vinegar and zip the bag closed before the fizzing gets out of control. You can zip the bag halfway closed, then stuff the packet in and zip the bag closed the rest of the way in a hurry, or you can put the time-release packet into the mouth of the bag and hold it up out of the vinegar by pinching the sides of the bag. Zip the bag closed and then let the packet drop into the vinegar. One way or another, get the packet in the vinegar and zip the bag closed.
Shake the bag a little, put it in the sink or on the ground, and stand back! The bag will puff up dramatically and then give a satisfying pop sound.

Build a Fizz Inflator

You will need:
One small empty plastic soda or water bottle
1/2 cup of vinegar
Small balloon
Baking soda
Funnel or piece of paper

Instructions:
Carefully pour the vinegar into the bottle.
This is the tricky part: Loosen up the balloon by stretching it a few times and then use the funnel to fill it a bit more than half way with baking soda. If you don't have a funnel you can make one using the paper and some tape.
Now carefully put the neck of the balloon all the way over the neck of the bottle without letting any baking soda into the bottle.
Ready? Lift the balloon up so that the baking soda falls from the balloon into the bottle and mixes with the vinegar. Watch the fizz-inflator at work!
What is happening?
The baking soda and the vinegar create an ACID-BASE reaction and the two chemicals work together to create a gas, (carbon dioxide) Gasses need a lot of room to spread out and the carbon dioxide starts to fill the bottle, and then moves into the balloon to inflate it.

Diet Coke and Mentos

Do this experiment OUTSIDE! Stand the Diet Coke upright and unscrew the lid. Put some sort of funnel or tube on top of it so you can drop the Mentos in at the same time (about half the pack is a good amount). Doing this part can be tricky if you don't have a specially designed geyser tube, I recommend buying one
Time for the fun part, drop the Mentos into the Diet Coke and run like mad! If you've done it properly a huge geyser of Diet Coke should come flying out of the bottle, it's a very impressive sight. The record is about 9 metres (29 feet) high!

Discuss what is happening: The thing that makes soda drinks bubbly is the carbon dioxide that is pumped in when they bottle the drink at the factory. It doesn't get released from the liquid until you pour it into a glass and drink it, some also gets released when you open the lid (more if you shake it up beforehand). This means that there is a whole lot of carbon dioxide gas just waiting to escape the liquid in the form of bubbles.

Dropping something into the Diet Coke speeds up this process by both breaking the surface tension of the liquid and also allowing bubbles to form on the surface area of the Mentos. Mentos candy pieces are covered in tiny dimples (a bit like a golf ball), which dramatically increases the surface area and allows a huge amount of bubbles to form.

The experiment works better with Diet Coke than other sodas due to its slightly different ingredients and the fact that it isn't so sticky

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