This is a blog of the 4th grade class in la Farigola de Vallcarca School in Barcelona. This year we are doing “Aula de Ciències” in English. In this blog we want to show you the experiments we do in our Science Lab. Science is fun!
- 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.
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.
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.
- 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.
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.
