Light sources and reflectors
Physics · Key Stage 1 · The School
Two kinds of bright thing
Some things make their own light. A torch. A candle. The Sun. These are called SOURCES. Other things only bounce light that is already there. A mirror. The Moon. A shiny spoon. These are called REFLECTORS. Both can look bright. Only one is making the light.
The dark room test
Take a torch and a mirror into a totally dark room. Turn the torch on. It still glows. It is a source. Now turn the torch off. The mirror goes completely dark too. It had no light of its own to give.
The Moon is a reflector
The Moon looks bright at night. It feels like a light source. It is not. The Moon only bounces light from the Sun back down to us. On a night with no Sun anywhere in the sky, the Moon would be completely black.
Sorting five bright things
Look at five bright things: a torch, a candle flame, a mirror, the Moon, a shiny coin. Ask one question about each: does it still glow with no other light around? The torch does. The candle does. The mirror, the Moon and the coin all go dark. Two sources. Three reflectors. Bright is not the test. Making its own light is the test.
Looking around for both kinds
Walk round your house and spot sources and reflectors. A lamp is a source. A window at night showing your own room back is a reflector. Streetlights are sources. Puddles at night are reflectors. Once you know the test, both kinds are easy to spot.