How big, and what shape

At a puppet show, the puppet is small. On the cloth screen, its shadow is huge.

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.

Now try it. Slide the object towards the lamp. Watch the shadow.

Try the lab to finish this lesson.