Air pressure

1986/02/01 Aizpurua Sarasola, Joxerra Iturria: Elhuyar aldizkaria

• Fisika

Drink a full glass of water and a plate. Pour water into the dish. Put a small cork on the water and a piece of paper on top. Then the fire is pressed and the fire is covered with the glass (of course, with the mouth under). What happens? The level of water inside the glass rises, doesn't it? The cause is that the fire burns oxygen from the air forming carbon dioxide. Part of this last compound is absorbed by the water, so being less of gas above the water, the pressure decreases and of course the water level increases.

Once this previous essay is done, we will go on to another essay. Take a full glass of water to the top edge. Then the mouth of the glass is covered by a sheet of paper. This sheet of paper should match the surface of water and the edge of the glass. Finally, turn the glass and discover that the water does not pour, but the paper is influenced by a tapo á.

When performing this last essay you will have to be careful as it does not always come out well and you can wet the floor of the house.

To finish today's program take a small bottle and fill it with water to the top edge. The entrance mouth with the thumb is covered by the bottle collate. The bottle is rolled and inserted in this position in a glass with water, the thumb is removed and the bottle is kept vertical. You will see that the water in the bottle is not low. It is also due to external air pressure.

Now we leave you under your ability.