Weight and the spring balance
Hang a bag on a hook. The hook is pulled down. What pulls it, and how hard?
Step 1 of 4
- A spring balance has a scale in newtons, N.
- Hang an object. The spring stretches.
- The pointer shows the weight in N.
- A big gap, between two big marks, is split into equal spaces. Divide to find each one.
The Earth pulls the bag, and the bag pulls the hook. A spring balance shows how hard, in newtons.
New words
- Weight — the pull of the Earth on an object. It is a force.
- Spring balance — a tool that reads weight from a spring's stretch.
The rule
Weight is the pull of the Earth on an object. It is measured in newtons. For the smallest reading, divide a big gap by its equal spaces.
A big gap is the distance between two big marks. The smallest reading is the smallest step you can read. Take a big gap of 1 N with 4 equal spaces. Then 1 ÷ 4 = 0.25 N.
| Scale | Big gap | Equal spaces | Smallest reading |
|---|---|---|---|
| 0 to 5 N | 1 N | 4 | 0.25 N |
| 0 to 20 N | 5 N | 5 | 1 N |
Watch out!
Count the spaces, not the small marks. Three small marks make four spaces.
Never hang more than the top mark of the scale. It could damage the balance.
Hang more and hang less. Read the pointer.
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