prism what happens when we shine white light into a prism? white light red lights bends the least...
TRANSCRIPT
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/η
sin(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”