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. Does it make light? Or does light bounce off it instead? Try it with five things.
No light, no seeing
In a very dark room you cannot see. It does not matter how wide you open your eyes. Cover a torch with your hand. Look at the red glow. Light is coming through your hand. Your eyes do not send light out. Light has to come IN to them. That is the one rule to remember.
Getting used to the dark
Sit in a dim room for a minute. You start to see more. Your eyes open wider to catch the little bit of light. That is why a torch in your face at night hurts. Your eyes were wide open for the dark. A sudden bright light is too much, all at once.
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. Shine a torch through it. The toy appears. Light arrived, and seeing arrived with it. Take the torch away. It is dark again, at once, because the light left.