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, 20 de desembre de 2010

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!

dimecres, 17 de novembre de 2010

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.

dimecres, 6 d’octubre de 2010

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.

divendres, 9 d’abril de 2010

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.

dijous, 4 de març de 2010

Paper chromatography

MATERIALS Paper towel Red, yellow and blue food colouring 1 glass Spoon Water Scissors An eye-dropper Water INSTRUCTIONS Drop one drop of red, one drop of yellow, and one drop of blue food colouring together on a glass. Mix the three drops together and observe the mixture. Cut a 3 cm strip of paper towel. Using the eye-dropper put a small drop of the food colour mixture in the centre of the paper towel strip about 3 cm from one end. Fill the other glass with water. Place the end of the paper towel strip with the food colouring dot into the water. Make sure the water does not touch the food colouring. Observe for 5-10 minutes. The water separates the food colouring mixture with separate portions of red, blue and yellow on the paper towel strip. WHY? Because the water creeps along the surface of the paper and dissolves the particles of colour. The components of the mixture move along the paper. The different colours do not move at the same speed because they all have different attractions to solvent and paper. WHAT DO YOU THINK ABOUT IT? WRITE YOUR OPINIONS!

dimarts, 23 de febrer de 2010

Magnetic pick up

MATERIALS: A strong magnet A paper clip Thread A piece of paper Clear tape Scissors Crayons
INSTRUCTIONS: Draw a kite and a rectangle in a piece of paper. Colour and cut them out. Put a paper clip on one corner of the kite. Tape a piece of thread to the opposite corner. Tape the other end of the thread to the rectangle. Tape the rectangle to a table. Hold the kite between your fingers and move the magnet away from the paper clip. The kite “flies”.
WHY?
Because a paper clip is made of metal and magnets have a magnetic field that attracts some kinds of metal. The paper clip does not have to touch the magnet to be pulled by magnetism.
WHAT DO YOU THINK ABOUT IT? WRITE YOUR COMMENTS.

dijous, 4 de febrer de 2010

Make a lava lamp

MATERIALS: -Food colouring. -Cooking oil -A plastic bottle -A funnel -Salt -Water
INSTRUCTIONS: 1. Put some water into the plastic bottle. 2. Add six drops of food colouring to the water. 3. Add a small quantity of cooking oil into the plastic bottle using a funnel. The cooking oil forms a layer on top of the water. 4. Mix everything. 5. Add some salt into the water. 6. Watch closely.
WHY? Oil and water don't mix because water is heavier. Oil makes a layer on the surface of the water. The salt sinks to the bottom and takes some oil with it. The salt dissolves in the water. Then, the oil floats back up to the surface.
WHAT DO YOU THINK ABOUT? WRITE YOUR COMMENTS.

dijous, 21 de gener de 2010

Fizzy Fun

Materials: Vinegar 2 glasses A piece of chalk (it is made of limestone) Several different rock types and minerals A magnifying glass

Instructions: - Pour a glass of vinegar into a glass. - Add a small piece of chalk (it is made of limestone). - Watch closely. After a few minutes, the piece of chalk starts to fizz. - Put another glass of vinegar into the other glass. - Put some different rock types and minerals into that glass (some of them contain limestone). - Watch closely. After a few minutes, some of them start to fizz and we can see bubbles.

WHY? Because vinegar is an acid and it dissolves small particles of calcium carbonate in the limestone (a mineral). We can see bubbles, because it releases carbon dioxide, a gas that rises to the surface. Rocks or minerals that contain calcium carbonate fizz. Those that don’t contain calcium carbonate won’t fizz.