LIGHT ENERGY – SOURCES &

REFLECTION OF LIGHT

Christine Tan4E

What is energy?• Energy is the ability to do __________.

• Energy has different forms. Can you name some of them?

work

Light energy

Sound energy Heat energyElectrical energy

Uses of light energy• Light energy helps us to __________.

• Plants use light energy from the sun to _____ ______ .

see

make food

Sources of light

• Anything that gives out light of its __________ is a source of light.

• The _____ is the Earth’s main source of light.

• Can you name other natural sources of light?

own

Sun

firefly lightning burning fuel

fireworks Glow-worm

Reflection of light• We see an object when light ____ on it

and _______ into our ______. falls

reflects

reflects eyes

moon

• The moon is not a source of light but appears bright because it ______ light from the ______. Sun

How colours affect reflection• We cannot see any colours on a black

object because the light has been _______ by the object.

• It is advisable for pedestrains to wear light coloured clothes at night because white or light coloured clothes _______all or most of the light and so can be seen at night.

absorbed

reflect

How surfaces affect reflection• Smooth surfaces reflect light well.

Where do you see smooth surfaces around you and why?

Lacquer, Varnish, Gloss, Wax, Polish

• Rough surfaces do not reflect light well.

Where do you see rough surfaces around you and why?

How colours affect reflection• Fluorescent colors

seem to be brighter because they can reflect more light. Discuss with your partner where you have seen them being used.