Light waves
Waves can also be A wave is passed across or through聽a material聽(medium), eg light waves are transmitted through air, glass and water. at the boundary between two different materials. When waves are transmitted, the wave continues through the material. Air, glass and water are common materials that are very good at transmitting light. They are Able to be seen through. because light is transmitted with very little absorption. Allows light to pass through but is not completely clear. materials transmit some light but are not completely clear. Lamp shades, shower curtains and window blinds are often translucent objects.
Colour filters
When white light passes through a coloured filter, all colours are absorbed except for the colour of the filter. For example, an orange filter transmits orange light but absorbs all the other colours. If white light is shone on an orange filter, only the orange wavelengths will be observed by the human eye.
Question
What colour will white light appear if it passes through a red filter then a green filter?
No colour will be visible. Nothing will pass through the green filter since only red has passed through the red filter and this will be absorbed by the green filter.
Scattering of light
Light can be scattered from particles that are present in liquids or in the air. For example, when milk is added to water then the small milk particles will scatter the wavelengths of light in all different directions, which is why milk looks white.
The very small molecules in the The layers of gases that surround the Earth. The important gases in the atmosphere are nitrogen, oxygen and carbon dioxide. scatter blue light the most - this is why the sky appears to be blue.
Small water droplets in clouds scatter all of the wavelengths in white light equally in all directions - this causes some clouds to appear white. However, larger droplets in rainclouds can absorb all of the wavelengths in light so that no light gets transmitted - this is why some clouds appear black.