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“Christmas isn't a season. It's a feeling.” – Edna Ferber

Sources of light


Let’s talk about sources of light in this lesson. Anything that gives out light of its own is a source of light.

 

Do you know the Earth’s main source of light? Yes it is the Sun. The Sun is the most important source of light.

 

What are sources of light?

 
Any source which can make light is a source of light.

 

E.g.- Sun and other stars, fires, torches, light bulb, lamps etc.
 
Also some animals like fireflies, glow-worms, are sources of light because they make their own light to attract mates.

 
Examples of sources of light
 
Light sources can be two groups.

 

  • Natural sources of light
  • Artificial sources of light

 

Following is a list of light sources;

 
Examples of natural sources of light
 
Natural light sources produce light naturally without any human involvement.

 

  • Sun
  • Stars
  • Lightning
  • Fireflies
  • Glowworms
  • Jellyfish
  • Bush fires

 
Examples of artificial sources of light
 
Artificial light is light made by humans.

 

  • Light bulbs
  • Torches
  • Lamps
  • Flame by matches
  • Candle
  • Lasers
  • Fireworks
  • When televisions and mobile phones are turned on

 

Reflectors of light

 

What are Reflectors of light?

 

Reflectors of light cannot make their own light. They just reflect light.

 
Examples of reflectors of light
 

Following is a list of light reflectors;

 

  • Moon
  • Mirrors
  • Smooth water
  • Metal
  • Smooth and shiny surfaces

 
Why are mirrors not sources of light?
 

Mirrors do not make their own light. They just reflect light. That is why you cannot see a mirror in a completely dark room.

 
Is the moon source of light?
 

No,it isn’t. The moon is not a source of light because it just reflects light from the Sun.

 

Remember! You must not look directly at the Sun because, Sun is a very bright object which can damage your eyes very quickly.

 

Invisible Light

 
Did you know there is invisible light that your eyes cannot see?
 

Infrared (IR) and Ultraviolet (UV) are the two types of invisible light.
 
Living things and very hot objects like the Sun give out infrared.
 
Ultraviolet is very powerful light that is given out by the Sun. UV light can damage your eyes. This is why you shouldn’t directly look at the Sun. Ultraviolet also causes severe sunburn and skin cancer. You should always remember to use sunscreen before exposing to the direct sunlight.

 

Also, read the lessons How Does Light Travel and Shadows.