How big, and what shape
At a puppet show, the puppet is small. On the cloth screen, its shadow is huge.
Step 1 of 4
- An object stands near the lamp.
- Its shadow on the screen is big.
- Now the same object stands near the screen.
- Its shadow on the screen is small.
Light spreads out from a lamp. The further it goes, the wider it spreads. So a screen far from the object shows a wider shadow. An object near the lamp is far from the screen.
The rule
An outline is the line round a shape.
Move the object nearer the lamp and its shadow grows. Move the screen back and the shadow grows too. Turn the object and only the outline changes.
| Move this | Which way | The shadow |
|---|---|---|
| The object | Towards the lamp | Grows |
| The object | Towards the screen | Shrinks |
| The screen | Further back | Grows |
Now try it. Slide the object towards the lamp. Watch the shadow.
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