Soapy froth

by Daiana and Corina

Materials you will need: vinegar.a Bowl, washing powder

Take a spoonful of soap powder and place it in the bowl Add several drops of the vinegar onto the soap powder in the bowl.

This reaction becomes a bubbling froth that gives off carbon dioxide gas. Once it finishes frothing, it leaves behind a salt substance that is not edible (DO NOT eat this salt). This chemical reaction is caused by the vinegar acting as the acid and the soda is the base.

Shiny coins

by Miruna and Beatrice

Materials you will need: paper towel , lemon, knife, plastic cup or bowl, dirty/old copper coins

Cut the lemon ans fill the cup/bowl with some lemon juice. Put the dirty copper coins in the juice and let them soak for a few minutes. Remove the coins from the cup/bowl and place on the paper towel..

Oxygen in the air reacts with copper, making a copper oxide coating. This is what makes copper coins dirty. The acid in the lemon juice reacts with the oxide and removes it from the coins – making then shiny copper coin.

Romanian team

The water does not spill

Experiment from Nicola

Needs:
glass, water and piece of papre


The glass is filled with water and covered with a sheet of paper. The water does not spill when we rotated the glass, because the paper is sucked to the glass of the pressure.

Home made video

Salt crystals

Experiment from Ania & Asia


Needs:
- water
- salt
- a glass or jar
- some tool (we used spoon)


Prepare saturated solution of salt water. Try to mix as much salt in wateras is possible. Put the tool into the glass. (You can also attach a piece of woollen yarn in the middle of the little stick). Put the glass in a warm place for a couple of weeks.

Observe the appearance of salt crystals. The grown crystals are in the shape of cuboids with shiny and smooth sides.

Eggs

Experiment from Kasia & Asia


Needed materials:

- 2 eggs (1 raw, 1 hard boiled)
- 1 litre jar
- salt

The way of carrying out the experiments:


Fill half of the jar with water. Prepare a solution of salt and water. Put the eggs into the solution in which the eggs should sink. Observe the movement of the eggs when a little amount of fresh (sweet) water is being poured in.

Raw eggs has a bigger density than water, that's why it sinks after putting it into the jar with fresh water. Adding salt to water, increases the wieght of water. The weight of fresh water is smaller than the weight of egg. Dissolving salt in water increases the force of uplift which acts on the egg.

Strong Air

Aids: a stick or a ruler, a big piece of newspaper Lay a ruler on a table.

Hit the ruler. The ruler flies away without breaking. Again, lay the ruler on the table and put a piece of newspaper on it so that there is no air under the newspaper. Flatten the piece of newspaper carefully. Quickly hit the ruler again. The ruler is broken.

The air above the piece of newspaper pushes it down with a big force. The ruler isn´t strong enough to lift the piece of paper. When you hit the ruler slowly, there is enough time for some air to flow under the piece of paper and to balance the air pressure under and above the paper.