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Light, reflection, refraction and colors


Author: Subject Coach
Added on: 15th Jan 2017

 

In this video lesson, we will discuss that Light from a source forms shadows and can be absorbed, reflected and refracted. We will learn about light rays, what opaque, transparent and translucent objects are.

 

Elaborations

  • drawing simple labelled ray diagrams to show the paths of light from a source to our eyes
  • classifying materials as transparent, opaque or translucent based on whether light passes through them or is absorbed
  • recognising that the colour of an object depends on the properties of the object and the colour of the light source
  • recognising the refraction of light at the surfaces of different transparent materials, such as when light travels from air to water or air to glass

 

Author: Subject Coach
Added on: 15th Jan 2017

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Transcript
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In this lesson we will discuss that Light from a source forms shadows and can be absorbed, reflected and refracted.

Light rays travel in straight lines from the light source.

When it hits an opaque object, some light is absorbed and the rest reflects off.
If the object is transparent, light rays pass through it easily.

If the object is translucent, some light can pass through, but the rest of the light will be reflected.

If you have ever put a straw in a drink, then you may have noticed that the straw appears to be bent under the water.

The reason for this is "Refraction"

Refraction is bending or change in direction of light.

When light moves from one substance to another it changes speed and direction. That change in direction is called refraction.

If you have ever put a straw in a drink, then you may have noticed that the straw appears to be bent under the water. The reason for this is Refraction

We can demonstrate this by splitting white light with a prism:

Wavelength of light defines its color

Light is made up of wavelengths of light, and each wavelength is a particular color. The color we see is a result of which wavelengths are reflected back to our eyes.

How the Colors Of An Object Depends On The Properties Of The Object And The Colors Of The Light

The colour an object appears depends on the colours of light it reflects. Book absorbed all the colours except red. Red is reflected that is why we see red.

Light from most light sources looks white, but actually contains all the colors of the spectrum; also known as the
rainbow

If an object looks blue, it is absorbing every color except blue, which is reflecting off it and entering your eyes.

If an object looks orange , it is absorbing every color except orange, which , again, is reflecting off and entering your eyes.

We see things because they reflect light into our eyes: