Light and dark
Physics · Early Years · The School
Where light comes from
The Sun is the biggest light SOURCE we have. A lamp, a torch, a candle and a screen all make their own light. The Moon does not — it shines because sunlight bounces off it. Point at things in the room and decide: does it make light, or does light bounce off it?
No light, no seeing
In a completely dark room you cannot see, however wide you open your eyes. Cover a torch with your hand and look at the red glow — light is going through. Eyes do not send light out; light has to come IN to them.
Getting used to the dark
Sit in a dim room for a minute and you begin to see more. Your eyes are opening wider to catch what little light there is. That is why a torch shone in your face at night hurts — your eyes were wide open for the dark.
Put a toy in a cardboard box and close the lid. Look through a small hole: you can see nothing, however hard you stare. Nothing dark went into the box — you simply stopped light getting in. Now poke a second hole and shine a torch through it. The toy appears. Light arrived, and seeing arrived with it. Take the torch away and it is dark again, instantly, because the light left.