Tuesday, November 30, 2010

Descomposition of hydrogen peroxide

En español

In english


Balloon in a plastic bottle

I will try to inflate a balloon in a plastic bottle.
You see it does not work.
There is a way to make it work. Just make a hole in the bottle.
Now it works because the air from the bottle can escape, and it lets the air from your mouth go into the balloon.


Tuesday, November 23, 2010

Hairdryer and balloon

We need: a hairdryer, an inflatable balloon, a tube Drop the balloon in the stream of air from the hairdryer. The balloon will start flying. The reason the balloon stays in the moving stream of air has to do with Bernoulli's Principle. Bernoulli's Principle says that pressure decreases inside a stream of flowing air. When the balloon begins to move out of this low pressure stream, the higher pressure of the air in the room pushes it back into the moving stream.

Air and water

Can you blow up a balloon without blowing? You will need: a plastic bottle, an inflatable balloon, a knife, scissors, a container with water Procedure: Cut out the bottom of the bottle. Pull the inflatable balloon on the neck of the bottle. Then dip the bottle vertically into water. Explanation: Water penetrates into the bottle because of the snipped bottom. Air has lower density, so it is always above the water. The water pushes the air into the balloon. Try, on the contrary, to depress the balloon into the bottle. Air and water do not mix together. Air is always on top.

Jumping coin

Expansion of gasses We need a bottle and a coin. Put the bottle in a fridge to cool. Rub soap and pour water on the neck of the bottle a little bit. Put the coin on the neck of the bottle to cover it. Put your hands on the bottle, hold it fast and think hard about making the coin jump. In a while, it works! Your hands warm the bottle, the bottle warms the air inside, and warm air wants to escape. When the pressure of the air is great enough, the coin jumps.

Monday, November 22, 2010

Cup hanger

You need a balloon and two cups. Blow the balloon up a little bit. Then place the cups to the balloon and continue blowing. When the balloon is big enough, drop the cups. The cups are stuck to the balloon. While blowing the balloon up, the air inside the cup was pushed away a little bit. The air pressure outside the balloon pushes the cup to the balloon.

Tuesday, November 16, 2010

Obedient balloon

For my experiment we need: a bottle, a kettle of hot water, a balloon, cold water to cool the bottle down

Close the neck of an empty bottle with a rubber balloon and then put the bottle into the kettle of hot water. The balloon is gradually inflated. The heated air in the bottle expands and the growing pressure causes the balloon on the neck of the bottle to inflate. Then cool the bottle, reducing the temperature of the air inside the bottle. Colder air has lower pressure. External atmospheric pressure pushes the balloon inside the bottle.

Saturday, November 13, 2010

Ballon & glass

Materials needed:

- balloon
- glass
- candle

Description of how to do:

We fill the balloon with air and tie it with a line. Then we light a candle and nat a glass. Now we must link glass with balloon.

Why doesn't the glass fall down?
Because pressure in the glass is smaller than pressure in the balloon.


Bernoulli's effect

Experiments from Kasia & Asia
Useful staff:
- ping-pong ball
- high power hair dryer
Desription of the experiment:
we put outletof the dryer vertically so that it blows thw air upwards. Next we out the ballin the stream of thw air. Now, we can observe the behaviour of the ball which floas in the stream of air. This is called the Bernoulli's effect.
The stream of the air equals the earthpull of the ball. The pressure outside the stream of the air is bigger than the pressure inside of it. The experiment shows us the development offorces gragging the ball into the streamof air. According to the lawof Bernulli the outgoingair from the dryer's outlet decreases the static pressure in favour of the createddynamic pressure. It (the dynamic pressure)upholds the ball towards the direction of the outgoing air. Whereas the reduced static pressure holds the ball perpendicularly towardsit. The ball floats freely in the air.


Diffusion in liquids

Experiment from Ania&Jessika

Materials needed:
- 2 glasses
- hot and cold water
- ink
Description of how to do:
Fill glasses halfway with water. One of them fill cold water, and the other with hot. Instill few drpos of ink on the surface of water (after it has stabilized). We can now observe the phenomenon of diffusion in liquids of different temperatures.
Diffusion is a spontaneous spread of one substances in another one. The rate of the diffusion depends on the temperaure of the liquid. Diffusion occurs more rapidly in liquids at the higer temperatures. This experience confirms the molecular strucure of liquid and the disordered motion of molecules.