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Light travels in straight lines.

If an object is transparent, it means you can see through the object clearly as light passes through it.

There are objects that let some light through, but not enough to allow us to see through objects clearly. We call these translucent or semi-transparent.

Objects that let no light through are opaque.

When an opaque object is placed in front of a light source, it prevents the light from passing through. This absence of light creates a dark shape on the surface behind it. This is called a shadow.

By moving the position of the light source, we change the size of the shadow.

• The closer to the light source an object is, the bigger the shadow will be. This is because the object blocks more of the light.

• The further away from the light source an object is, the smaller the shadow will be. This is because the object blocks less of the light.

• When the light source moves directly above an object, the shadow will be directly below the object.

• When the light source is to one side of the object, the shadow will appear on the opposite side and the shadow will be longer.

Have a go at creating your own shadow puppets.

You will need: a light source, your hands and a wall or alternatively you could make some puppets out of card, a white sheet and a light source.

Watch this clip below to learn more about shadow puppets.

Experiment with different objects around your house to create shadows.

Which object makes the smallest shadow? Which object makes the biggest shadow?

You might want to:

• experiment with different light sources
• experiment with transparency of different objects

You could also make a list of all the transparent objects and translucent objects you can find around your house.