The same push, spread out
A drawing pin goes into a board with a light push. Your thumb presses just as hard on the other side. It does not hurt.
Force is measured in newtons (N). Area is measured in square metres (m²). Pressure is measured in pascals (Pa). A face is a flat side of a box.
Step 1 of 3
- A box weighs 60 N.
- On a small face of 0.1 m², it presses 600 Pa.
- On a big face of 0.6 m², it presses only 100 Pa.
New word
- Pressure — the force on each unit of area.
The rule
The pin's tip has a tiny area, so its pressure is high. Your thumb has a wide area, so its pressure is low.
Pressure is force divided by area. Its unit is the pascal (Pa), one newton on one square metre. The same force on a smaller area gives a higher pressure.
For the box, 60 N ÷ 0.1 m² = 600 Pa. And 60 N ÷ 0.6 m² = 100 Pa.
| Force | Area | Pressure |
|---|---|---|
| 90 N | 3 m² | 30 Pa |
| 90 N | 1 m² | 90 Pa |
Slide the area. Watch the pressure.
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