Thursday, December 3, 2009

Do you have that sinking feeling?

Quicksand is used a lot in movies that you see on TV. However, do you actually believe that it can pull anything down? Let's find out with this fun and easy experiment.

What you will need:

- one cup of maize cornflour
- half a cup of water
- a large plastic container
- a spoon

Please, do not try to do this in the classroom. If accidentally knocked over, there could be a hard day's work involved in just cleaning it up! The first step is very simple, just mix the cornflour and water thoroughly and your quicksand is made, but wait, here comes the fun part. Stir the mixture slowly and drip the quicksand, just so everyone knows it is a liquid.

If you stir it quickly, it will become hard which means that you can poke it, but try to poke it quickly, not hard. Maybe afterwards you should see if a small ball or something can be sucked down. Although, I can't guarantee anything. Remember to always stir instant quicksand before using it.

Did it work?

If you add just the right amount of water to the cornflour it becomes very thick, if you stir it quickly! This is because the cornflour grains are mixed up, and they can't slide over each other. Stirring slowly allows more water in between the cornflour grains, which makes it easier for them to slide over one another.

Remember, this is an outside activity, unless you want to be cleaning up all day!

Experiment written by SK.

Wednesday, December 2, 2009

Floating Eggs

We all know that a rock can’t float, but can an egg?
Is there any way to make an egg float? Well, it’s easy to make an egg float with one simple ingredient, salt.

What you will need:
- one egg
- water
- salt
- a tall drinking glass

Pour water into your glass until it is about half full, (and I do mean about half full, not any measurements). Stir in lots of salt, about six tablespoons, and then fill the glass until it is almost full with plain water. Pour the plain water in gently - slowly, so that it doesn't mix up the heavier salt water.

Now, gently lower the egg into the water and watch what happens.

Well, did it float or not?

Denser liquid is easier for things to float in. So, because tap water is less dense than salt water, the egg sinks through the tap water, and floats in the salt water! Which means you have an egg in the middle of your glass. If you were careful putting the plain water in with the salt water, they would not have mixed, which means you have two different types of water in one glass.

Don’t crack the egg in this experiment, it could be messy!

Written by SK on 2 December 2009.

P.S. Can you name any rocks that actually will float? Have a look here.

Change your shape

Would you like to change your shape?
Well it's easy with our get-fat-quick chocolate recipe!
After a few helpings you will certainly be a different size!

4 tablespoons s.r. flour (cake flour)
4 tablespoons sugar
2 tablespoons cocoa
1 egg
3 tablespoons milk
3 tablespoons oil
3 tablespoons chocolate chips (optional)
A small splash of vanilla extract
1 large coffee mug

Add dry ingredients to your largest mug and mix well. Add the egg and mix thoroughly. Pour in the milk and oil and mix well. Add the chocolate chips (if using), vanilla extract then mix again.

Put your mug in the microwave and cook for 3 minutes at 1000 watts (high).
The cake will rise over the top of the mug, but don't be alarmed!

Allow to cool a little, and tip out onto a plate if desired.

Microwaves use radiowaves to heat food. Heat is made when radiowaves are absorbed by water, fats and sugars. Metal reflects microwaves, which is why we needed to use a coffee mug instead of metal for this recipe. Did you know that if you set a microwave to a higher heat than it should be set to, the outside of the cake will actually burn before the inside is cooked?

Don't eat it before it's cool. We hear that adding a scoop of icecream cools it down quickly.