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How we see light

Rebekah Rawsthorne

Created on February 2, 2022

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Transcript

Light - What are light sources?

What do we already know about light?

https://www.youtube.com/watch?v=1PsHHKwtXQU

Where does light come from?

Light comes from a source. There are natural light sources and man made light sources.

Which light sources here do you think are natural and man made sources?

True or False

A mirror

Water

The moon

These are sources of light

True or False

A mirror

Water

The moon

These are sources of light

False!

The moon, water and mirrors are not light sources. Instead they reflect light from other sources!

How does light help us to see?

Light travels as a wave. But unlike waves of water, it does not need any medium to travel through. This means light can travel through a vacuum - a completely airless space. Light waves travel out from sources of light in straight lines. These lines are often called rays or beams of light.

How do we see?

Light is reflected from an object to your eye. Light from the light source travels in a straight line and hits the object. The ray of light is reflected off the object and travels in a straight line to the eyes, enabling ud to see the object.

Remember: Light does not shine from the eyes (like a torch) for us to see.

How do we see?

  • 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.

https://www.bbc.co.uk/teach/supermovers/ks2-science-light-reflection-and-shadows-from-the-tardis/zdchd6f