8K LIGHT

Optical Illusions

Which is darker A or B?

Black spots appear at the intersections.

The grey centre bar is the same shade everywhere! - Watch

Move your head forwards and backwards while looking at the black dot. What appears to happen?

There is a pipe in the stream of water that holds up the tap and supplies the water!

Focus on the cross in the middle – what happens?

Rabbit or duck?

Circle or spiral?

This is a circle – honest!

The thick black lines are parallel.

B or 13?

You guessed it. The red lines are straight.

How many legs?

Young lady or old lady?

Really truly nothing is moving here!

Can you see the 10 in the orange circle?

What number is visible in the coloured circle? If you are colourblind you may see no number – like the grey image.

Practical and sporty

Can you find mother and child?

A dog in the snow

Now can you see him?

TED talk optical illusions

Light introduction How does light travel? Define: – Transparent – Translucent – Opaque

Use the ray box to test if the objects are transparent, translucent or opaque TransparentTranslucentOpaque

Opacity t/opacity.asp?strReferringChannel=learningtea chingandassessment&strReferringPageID=tcm : t/opacity.asp?strReferringChannel=learningtea chingandassessment&strReferringPageID=tcm :

Luminosity What does luminous mean? Name 3 luminous objects. Is the moon luminous? Explain.

Plane mirrors What happens to a ray of light when it hits a mirror? What is the imaginary line at 90° to the mirror called? What is the ray that goes to the mirror called? What is the ray that goes away from the mirror called? What is the rule for the angle of incidence and angle of reflection?

Reflection Plane mirror Normal Incident ray Angle of incidence Angle of reflection Reflected ray

RULE ANGLE OF INCIDENCEANGLE OF REFLECTION

Light through a glass block What happens to light when it passes from air to glass or vice versa? What is this called?

Refraction Incident ray Normal Emergent ray Normal

Refraction When light passes from air to glass the angle of incidence is ____________ than the angle of refraction. When light passes from glass to air the angle of incidence is ____________ than the angle of refraction.

White light What colour is white light? What happens when you shine white light through a prism? Why does this happen?

Light through a prism How many colours are produced when light passes through a prism? What is this separation of colours called? Which colour is refracted the most? Which colour is refracted the least?

Dispersion through a prism

Colours What are the primary colours of light? How can we get these colours – Magenta – Cyan – Yellow

Colour mixing ighting.asp?strReferringChannel=learningteac hingandassessment&strReferringPageID=tcm:

R B G

Filters What are colour filters? Which word means the light passes through the filter? Which word means the light does not pass through?

1. What colour(s) will be transmitted by the red filter? redblue 2. What colour will we see on the screen? Answer : red screen Answer : black 3. Why? Answer : the blue filter absorbs the red light.

1. What colour(s) will be transmitted by the green filter? 2. What colour will we see on the screen? Answer : green Answer : black 3. Why? Answer : the blue filter absorbs the green light. greenbluescreen

1. What colour(s) will be transmitted by the yellow filter? 2. What colour will we see on the screen? Answer : green and red Answer : red 3. Why? Answer : the red filter absorbs the green light and transmits red light. yellowredscreen

1. What colour(s) will be transmitted by the yellow filter? 2. What colour will we see on the screen? Answer : green and red Answer : green 3. Why? Answer : the cyan filter absorbs the red light and transmits green light. yellowcyanscreen

Colour filter questions

Why we see colours Why do objects appear coloured in white light? Explain what happens for a white object. Explain what happens for a black object.

I think that the light is reflected by the object and goes to your eye. I think that the light goes to your eye, then to the object.

If the light from the lamp is white light, made up of seven colours. Why do we see it as red?

Only red is reflected Orange, yellow, green, blue, indigo and violet are absorbed

All the colours are reflected

All the colours are absorbed

Red green 5. Red red 6. Green yellow 7. Blue magenta 8. Yellow cyan 9. Magenta yellow 10. Blue white 2. Yellow red 3. Cyan blue 4. In your exercise book... - write the title and date - draw and complete each diagram with the correct reflected colour The first one is done for you. Coloured objects in coloured light. Red white 1. red

Filters t/filters.asp?strReferringChannel=learningteac hingandassessment&strReferringPageID=tcm: t/filters.asp?strReferringChannel=learningteac hingandassessment&strReferringPageID=tcm:

Lenses What are the two different types of lenses? And what does each one do to the light? Where do we use lenses?

Aim: To investigate the two different types of lenses