Prism

What happens when we shine white light into a prism?

White light

Red lights bends the least

Violet light bends the most

Many colours blended together

Copy please

Last lesson

• Refraction of light

Refraction

Glass block

Beam of lightLight going from air to glass bends towards the normal

Light going from glass to air bends away the normal

The mug trick!

The mug trick!

Homework – To show and explain this to your parents! Due

Friday 29th Jan

Prism

What happens when we shine white light into a prism?

White light

Red lights bends the least

Violet light bends the most

Many colours blended together

Today’s lesson

• Total Internal Reflection• Fibre-optic cables• Seeing colours

Another little investigation!

Aim all beams at the centre of the semi circle

Another little investigation!

Aim all beams at the centre of the semi circle

Total Internal Reflection

Critical Angle?

Critical Angle?

Critical Angle?

Critical Angle?

Critical Angle?

Critical angle

Total Internal

Reflection

If the angle is bigger than the critical angle we get total internal reflection

Copy please!

Total Internal

Reflection

Critical angle

sin c = 1/ηsin(critical angle) = 1/(refractive index)

Examples of Total Internal Reflection

Examples of Total Internal Reflection

Examples of Total Internal Reflection

Examples of Total Internal Reflection

Examples of Total Internal Reflection

Examples of Total Internal Reflection

Seeing and colours

We see things because light is reflected into our eyes

Red objects only reflect red light

A Red objects in green light would look black (no reflected

light)

Combining lightYouTube - Bill Nye the Science Guy - 16 - Light and Color 1/3

YouTube - Bill Nye the Science Guy - 16: Light and Color 2/3Related Videos

Let’s try some questions!“Coloured lights”