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Lesson 2 of 14

A shadow is a place light did not reach

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At noon, a neem tree makes a dark patch on the ground. Step into it, and the strong, bright light stops.

A lamp, an object, and a wall stand in a row.
Step 1 of 4
  1. A lamp, an object, and a wall stand in a row.
  2. Light leaves the lamp and travels straight.
  3. The object blocks the rays, or light paths, that hit it.
  4. The dark patch on the wall is the shadow.

The new word

  • Opaque — stops light completely. No light gets through it.
  • Transparent — lets light pass. Translucent — lets some through, so its shadow is faint.

The rule

An outline is the line round a shape.

A dark shadow needs light, something , and a surface behind it. Take any one away and it goes. A shadow shows only the outline of the object, not its colour.

What a shadow needs
WhatAn example
Something making lightThe Sun, a torch
Something opaqueA tree, a tumbler
A surface behindA wall, the ground

Now try it. Switch each part on and off. When is there a shadow?

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