Facts At Your Fingertips: Energy and forces – Using light
We need light to see the world and to find our way around it.
In the earliest days of humanity, we just used the natural light produced by the Sun and went to bed when it got dark. Today, we can also use artificial lights to illuminate the world.
How the eye sees
Light travels into the eye and is focused by the lens to create a clear picture on the retina at the back of the eye.
This picture is actually upside down, but the brain turns the image the right way up so we can understand it.
Telescopes
Telescopes collect light from distant objects, such as planets and stars.
Lenses and mirrors within the telescope then bend the light rays to make a clear image of the object, making it seem closer than it really is.
Camera
Like our eyes, cameras collect and bend light to produce a clear picture.
The camera lens focuses light into an image, which is recorded on light-sensitive film or a light-sensitive microchip.
Lighting the dark
Electric lights convert electrical energy into light.
In an incandescent light bulb, this is done by heating a thin piece of metal until it glows. In compact fluorescent lights, electricity is passed through a gas, causing the lamp’s phosphor coating to glow and create light.