A world of colours
In 1666 the scientist Isaac Newton passed sunlight through a triangular piece of glass called a prism. The white light split into seven colours. These seven are called the spectrum, or the colours of the rainbow. Their order never changes: red, orange, yellow, green, light blue, blue, violet. An object absorbs part of the light that falls on it and reflects part. We see the reflected colour: a red flower reflects red light and absorbs the others. A black surface absorbs almost all light and a white surface reflects all of it.
Experiments: 1) “Newton’s disc”: divide a cardboard circle into 7 sectors, colour them as the rainbow, push a pencil through the centre and spin fast: colours blend and look whitish-grey. 2) “My own rainbow”: on a sunny day stand with your back to the Sun and spray a fine mist of water: a rainbow appears. Learn the colours in order: red, orange, yellow, green, light blue, blue, violet. Safety: do not look at the Sun.