Sir Isaac Newton held the theory that light was made up of tiny particles. In 1678, Dutch physicist, Christian Huygens believed that light was made up of waves vibrating up and down to the direction of the light travels.
Light travels as waves. The direction of vibration in the waves is at 90° to the direction that the light travels.
Light travels in straight lines.
Unlike sound waves, light waves can travel through an empty space but scientifically known as a vacuum. They do not need a substance to travel through, but they can travel through transparent and translucent substances.
Light travels in straight lines.
Unlike sound waves, light waves can travel through an empty space but scientifically known as a vacuum. They do not need a substance to travel through, but they can travel through transparent and translucent substances.
REFLECTION
|
A plane mirror is a flat mirror. When you look into a plane mirror, you see a reflected image of yourself or an object.
.Light waves change speed when they pass across the boundary between two substances with a different density, such as air and glass. This causes them to change direction, an effect called refraction.
Light can be focused so that it appears to meet at a single point. Focusing is important for getting clear images in our eye or in photos/pictures. Images that are not focused appear blurred. A pinhole camera consists of a box or tube with a translucent screen at one end and a tiny hole also called the pinhole; made in the other end. Light enters the box through the pinhole and is focused by the pinhole onto the screen. The image is upside down and smaller than the object.
White light is a mixture of many different colours, each with a different frequency. White light can be split up into a spectrum of these colours using a prism, a triangular block of glass. Light is refracted when it enters the prism, and each colour is refracted by a different amount. This means that the light leaving the prism is spread out into its different colours, a process called dispersion.
the seven colours of the spectrum are : red , orange , yellow , green , blue , indigo , violet
There are three primary colours in light: red, green and blue. Light in these colours can be added together to make the secondary colours magenta, cyan and yellow. All three primary colours add together make white light.
the seven colours of the spectrum are : red , orange , yellow , green , blue , indigo , violet
There are three primary colours in light: red, green and blue. Light in these colours can be added together to make the secondary colours magenta, cyan and yellow. All three primary colours add together make white light.
Cameras and our eyes detect light.Cameras are devices that focus light from an object onto a photo-sensitive material using a lens. In an old-fashioned camera they used camera films. When the film absorbed light, a chemical change produced an image in the film. This was used to create a picture on photo-sensitive paper. In a modern camera or the camera in a phone, the photo-sensitive material produces electrical impulses, which are used to make an image . This can be viewed on the screen, or sent to a printer. The eye focuses light from an object onto a photo-sensitive material just like a camera. However, in the eye, this material is the retina. The retina contains cells that are sensitive to light.
|