Lesson 3 of 14
The air presses on everything
Show on a big screenBlow up a balloon. It swells in every direction. The air inside is pressing on its walls.
Step 1 of 2
- A column of air stands above a small sheet.
- Above a bigger sheet stands more air, so the push is bigger.
New word
- Atmosphere — the layer of air around the Earth.
The rule
Air is a layer around the Earth called the . It has weight, so it presses on everything, in every direction. This is atmospheric pressure.
| Square sheet | Push of the air |
|---|---|
| 10 cm by 10 cm | about 1000 N |
| 20 cm by 20 cm | about 4000 N |
The 20 cm sheet is 4 times bigger in area. So it gets 4 times the push.
A 1 kg bag of sugar weighs about 10 N. So 4000 N is the weight of about 400 kg.
Change the sheet. See the push of the air.
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Try the lab to finish this lesson.