A telephone

MATERIALS:
- Two plastic glasses
- 6 - 8 m. of fishing line
- 2 clips
- a cutter


INSTRUCTIONS:
- Make a hole on the bottom of the plastic glasses.  
- Put one end of the fishing line into the hole.
- Make a knot to a clip. Do the same with the other end.
- Tighten the fishing line and talk to a friend.


WHY?:
The  sound travels better through a solid (fishing line) than the air.

Lung capacity

MATERIALS:
- A tank
- A tube
- A plastic bottle with capacity measures
- Water

INSTRUCTIONS:
- Fill the tank with water.
- Fill the bottle with water and put the tube in it.
- Put the bottle upside down in the tank.
- Fill your lungs and blow in the tube.
- Look at your lung capacity in the bottle.

WHY?
You fill your lungs as much as you can and  when you blow through the tube, all this air goes into the bottle and expels the water in the bottle, it occupies its place.

WRITE YOUR COMMENTS!:

The candle goes out

MATERIALS:
- A candle
- A plate
- A glass
- Matches or a lighter
- Water


INSTRUCTIONS:
- Place the candle on the plate.
- Pour some water into the plate.
- Light the candle.
- Put the glass upside down on the plate.
- Look at the flame and the water in the glass.


The flame goes out and the water level in the glass rises.


WHY?
The candle flame heats the air in the glass, and this hot air expands. Some of this hot air escapes out from under the glass  (you can see some bubbles). When the flame goes out, the air in the glass cools and contracts. The cool air inside of the glass creates a vacuum due to the low pressure inside the glass and the high pressure outside of the glass. 



WRITE YOUR COMMENTS!:

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!:

Ball-egg

MATERIALS:


Two glasses

Two eggs

Vinegar

Water

INSTRUCTIONS:

- Fill a glass with water and put one egg into it.

- Fill the second glass with vinegar and put another egg in.

- Wait three or four days.

- The egg in vinegar hasn't got a shell. It's bigger and darker than the egg in water.

WHY:

Vinegar is an acid and dissolves the calcium in the eggshell. It is calcium that makes the shell hard. A thin flexible membrane just under the shell still holds the egg's shape.

Water does nothing to the eggshell.

WRITE YOUR COMMENTS!

Colour Splash

Colour Splash on PhotoPeach

MATERIALS:
- 3 glasses
- oil
- water
- food colouring
- a spoon


INSTRUCTIONS:
1)- Fill a glass with water.
- Add some drops of food colouring.
- Water and food colouring mix.
2) - Fill a second glass with oil.
- Add some drops of food colouring.
- Stir with the spoon.
- Food colouring stays a little ball. It doesn't mix.
3) - Fill a third glass with water and some oil (a thin layer).
- Add some drops of food colouring.
- The colouring food drops don't mix and they sit in the oil layer, like floating.


WHY?:
1) - Food colouring is mainly made of water, so it can mix with water.
2) - As food colouring is made of water, it can't mix with oil. It forms balls.
3) - Each drop of food colouring is coated with oil, so the drops float on the oil layer. When you break the oil "coat", they mix with water.


WRITE YOUR COMMENTS!:

Atmospheric pressure

atmospheric pressure on PhotoPeach

MATERIALS: A can Cooking tongs A camping stove A bowl with cold water INSTRUCTIONS: - Put some water in the can (a tablespoon). - Place the can on the stove. - Heat the can to boil water. You can see the water vapor rising from the can. Wait one minute. - Hold the can with the tongs. - Take the can, turn it upside down very quicky and dip it into the water in the bowl, so the hole is covered by water. - The can crushes. - We did the same, but we placed it on the water with the open on the top: it happened nothing. WHY?: By boiling the water, the water changes states from a liquid to a gas (vapor). The water vapor expands and pushes the air out of the can into the atmosphere. When we turn the can upside down and place in the water, the water vapor cools, condenses, contracts and the pressure in the can decreases. Then the pressure from the outside of the can (atmospheric pressure) is higher, pushes the can and crushes it . When we do the experiment with the opening on the top, the air from the outside goes in the can and the pressure in and out the can is balanced.

Bottled eggs-periment

MATERIALS:

- A peeled boiled egg.

- A glass bottle with an opening a little bit smaller than the egg.

- A newspaper.

- A lighter.

INSTRUCTIONS:

- Put some pieces of newspaper into the bottle.

- Light a piece of paper and put it into the bottle to burn the pieces of newspaper.

- Wet the egg and place it in the bottle opening.

- The egg will slowly move into the bottle.

WHY?:

Hot air expands and cold air contracts. When you heat the air in the bottle, the molecules inside the bottle spread out and the air pressure is increased. When the air in the bottle cools, the air pressure decreases. Then the outside air pressure is higher than the pressure in the bottle, and pushes the egg into the bottle.

WHAT DO YOU THINK ABOUT IT? WRITE YOUR OPINION.

Lung capacity

Lung capacity on PhotoPeach MATERIALS: - A tank - A tube - A bottle INSTRUCTIONS: - Fill the tank and the bottle with water. - Put the bottle upside down in the tank. - Put the tube in the bottle. - Fill your lungs with as much air as you can. - Blow through the tube. - Measure how many liters you have blown. WHY?: The air you blow through the tube expels the water in. The place were once there was water now there is air. You can measure the air you blow looking at the level of water in the bottle. WHAT DO YOU THINK ABOUT IT? WRITE YOUR COMMENTS.

Fatty foods

Fatty foods on PhotoPeach

MATERIALS:

Brown grocery paper, cut into small squares. Different foods to test: crisps, peanuts, apple, banana, butter, mayonnaise, oil, chocolate, cheese, nuts, popcorn, ham... INSTRUCTIONS:

- Rub each piece of food onto separate paper squares. Count to 20 while you rub, so that you test each food for the same amount of time.

- Label the squares so you remember which food you rubbed on each one.

- Put the papers in order from the most stained to the less.

- Leave them a week (an overnight is enough).

- After a week, put the papers in order again. You'll see that the order is different now.

WHY:

Fat stains the paper while other liquid substances (mostly water) evaporate.

WHAT DO YOU THINK ABOUT IT? WRITE YOUR COMMENTS.

International Year of Chemistry: a workshop.

Josep's mum, Núria , is a chemist. She came to school and did lots of experiments to us: a battery with a lemon, small pieces of paper that showed if a liquid was acid or basic, liquids that changed colour when adding some drops of another liquid... We thought they were magic!

When she finished we asked her many questions.

WHAT DO YOU THINK ABOUT IT? WRITE YOUR COMMENTS!

International Year of Chemistry: no fire for a fried egg

MATERIALS:

- An egg.

- A plate or a bowl.

- Alcohol.

INSTRUCTIONS:

- Break the egg and put it in the plate.

- Pour some alcohol on it.

- Wait half an hour.

- It's a fried egg!

WHY?

Eggs contain proteins. When you heat proteins they undergo a structural change called denaturation. You can get the same result with alcohol. In this process the egg white becomes solid and white.

WHAT DO YOU THINK ABOUT IT? WRITE YOUR COMMENTS!

International Year of Chemistry: the balloon

MATERIALS:

- A bottle.

- A balloon.

- Vinegar.

- Sodium bicarbonate.

- A funnel.

INSTRUCTIONS:

- Fill half of the bottle with vinegar.

- Fill the balloon with sodium bicarbonate. Use the funnel.

- Adjust the balloon to the bottle.

- Pour the bicarbonate to the vinegar.

- The balloon starts to blow up.

WHY?

When bicarbonate mixes with vinegar (an acid) it produces carbon dioxide. This is the gas that blows the balloon up.

WHAT DO YOU THIN ABOUT IT? WRITE YOUR COMMENTS!

International Year of Chemistry: Physical or Chemical change?

MATERIALS:

- 2 plates - 2 sheets of paper - a lighter INSTRUCTIONS: - Make a ball with one of the sheets and place it on a plate. - Fold the second sheet of paper, place it on the plate and burn it. - The first sheet has suffered a physical change, and the second one a chemical change. WHY? The first sheet of paper is still paper, it keeps its properties. It has only changed its shape and size: it's a physical change. The second sheet of paper isn't paper any more. Now it's something different, it's ash: it's a chemical change. WHAT DO YOU THINK ABUOT IT? WRITE YOUR COMMENTS!

Building bridges

MATERIALS:

4 thick books

1 piece of cardboard

paper clips

rubbers

INSTRUCTIONS:

Put the books in two piles about 15 cm apart.

Lay the piece of the cardboard on the books.

Put paper clips on the cardboard. Count them. The "bridge" starts to sag. Finally the bridge collapses.

Now make another bridge, but bend the piece of cardboard into an arch between the books.

Put paper clips and rubbers until it collapses.

This bridge is stronger than the first one.

WHY?

The first bridge collapses before because it is flat and it has to take all the weight.

In the second bridge the weight goes to the sides and it is shared by the books, so the card can support more weight.

WHAT DO YOU THINK ABOUT IT? WRITE YOUR COMMENTS.

Jumping egg

MATERIALS:

Two glasses

Two eggs

Vinegar

Water

INSTRUCTIONS:

- Fill a glass with water and put one egg into it.

- Fill the second glass with vinegar and put another egg in.

- Wait three or four days.

- The egg in vinegar hasn't got a shell. It's bigger and darker than the egg in water.

WHY:

Vinegar is an acid and dissolves the calcium in the eggshell. It is calcium that makes the shell hard. A thin flexible membrane just under the shell still holds the egg's shape.

Water does nothing to the eggshell.

Discopaper

Materials: - A bowl - An elastic band - Plastic film - Toilet paper - A radio Instructions: Stretch a piece of plastic film across the top of the bowl. Lay tiny pieces of toilet paper on. Place the bowl next to the radio. Turn on the radio. Turn up the volume. The toilet paper starts to move. Why: The sound from the radio makes air vibrate. If the music is very loud, vibrations are stronger. Vibrations make the plastic film vibrate, so the tiny pieces of toilet paper move too. Different styles of music have different speeds of vibration.