Shadow colour

The idea

Changing the colour of an opaque object does not change the colour of its shadow.

A red card

A red opaque card is held in front of a lamp, with a wall behind.

What colour will the shadow be?

• A red shadow
• A dark shadow
• It depends on the lamp

Change the colour

Try cards of four colours. Look at the shadow each time.

Same shadow

Red, blue, green or yellow, the shadow looked the same. A shadow is a place where light does not reach.

Changing the colour of an opaque object does not change the colour of its shadow.

Notes

Changing the colour of an opaque object does not change the colour of its shadow.

Check yourself

A blue card and a yellow card are used in turn. Their shadows are …

What does changing the colour of an opaque object do to its shadow’s colour?

Why is the shadow of a green card not green?

Which statement is right?

• both green. Shadows do not turn green. Both are dark.
• blue and yellow. The shadow does not take the colour of the card.
• the same dark colour — correct. Yes! The colour of the card does not change its shadow.
• Nothing, the colour of the shadow does not change — correct. Yes! It stays the same.
• It makes the shadow the same colour as the object. The colour of the shadow does not change.
• It makes the shadow lighter. A shadow from an opaque object stays just as dark.
• Shadows always take the colour of the lamp. A shadow is a dark patch. It does not take any light colour.
• A shadow is the dark place where light does not reach — correct. Yes! No light reaches there, whatever the card’s colour.
• The card is not painted properly. Painting the card does not change its shadow.
• Only a blue object makes a dark shadow. An opaque object of any colour makes a dark shadow.
• A red object makes a red shadow. The colour of the object does not colour its shadow.
• Changing the colour of an opaque object does not change its shadow’s colour — correct. Yes! The shadow stays the same.