Obscura
A camera is basically a box that lets in light. It comes from a Latin expression - camera obscura - which means 'dark chamber'.
A camera has to have a 'hole' that lets in light. This is called an 'aperture'. The hole can only open briefly. This is done by using a 'shutter'. A shutter usually opens for a tiny fraction of a second. But sometimes at night the shutter can be left open for a long time.
In the old days, cameras needed film to record the light that comes into the box. Nowadays most cameras are digital. They record the light coming into the box using a 'sensor'.
Flickering images
For a long time, people understood that photography was possible. One of the problems was how to fix what the camera saw. Nearly 1,000 years ago, an Iranian scientist invented a device that reflected images. Around 300 years ago, scientists developed a way of recording images on a plate of glass with chemicals on it. Photography became much easier when film was developed. The first film was made in 1885 in the US by Eastman Kodak.
