Liquid or solid?

Liquid or solid? on PhotoPeach



 
MATERIALS:
- Cornflour
- Water
- A bowl
- A spoon

INSTRUCTIONS:
- Put two glasses of cornflour into the bowl.
- Add a glass of water and four or five drops of food colouring.
- Mix everything.
- Make a ball in your hands. Is it a solid or a liquid?
- Hold it up in your hand. Is it a solid or a liquid?

WHY?
The mixture is solid and liquid at the same time.
Cornflour is made of lots of long tiny particles (molecules) which don't dissolve in water but spread themselves out. When you make a ball in your hands the particles join together and it looks like a solid; but when you hold it up the particles slide over each other and it looks like a liquid.

WRITE YOUR COMMENTS!:

Floating egg

MATERIALS:
- 1 egg
- A glass of water
- A spoon
- Salt


INSTRUCTIONS:
- Fill the glass with water.
- Put the egg into the glass.
- The egg sinks.
 
- Add two spoonfuls of salt.
- Stir.
- Add more salt until the egg starts to float.

WHY?:
Salt water is denser than tap water. When water becomes salty enough, the egg weights less than water, so the egg floats to the top.

WRITE YOUR COMMENTS!:

Water filter

MATERIALS:
- A plastic water
- Two glasses
- A piece of cotton wool
- Sand
- Sawdust
- Small stones
- Bigger stones
- Dirty water


INSTRUCTIONS:
- Cut the bottom of the bottle.
- Turn it upside down and place the materials in this order: cotton wood, sand, sawdust, small stones and big stones.
- Place the bottle in a glass.
- Pour some dirty water.
- Water is cleaner when it comes out.


WRITE YOUR COMMENTS!:

What temperature does water boil in Tibet?

We haven't been able to take photos of the experiment, but here you have a video about it:

http://youtu.be/eIUjsIuXgUE


MATERIALS:
- A jar with its lid
- Water
- A stove or microwaves
- A bag with ice
- A dishcloth
- A thermometer

INSTRUCTIONS:
- Fill the jar with water and heat it.
- Wait until water is boiling.
- Close it quickly.
- Put the bag of ice onto the lid to cool the air in the jar.
- Water starts boiling again.
- Open the jar and check the temperature.
- It's 80 degrees.

WHY?:
When we close the jar, the air on the top is very hot. When we cool it with ice, its volume diminishes and so does the pressure. This pressure is similar to the one in Tibet.

WRITE YOUR COMMENTS!: