Welcome!

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!


dilluns, 26 de març de 2012

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.

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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. 



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dilluns, 30 de gener de 2012

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.

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dimarts, 10 de gener de 2012

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.

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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.


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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.

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