1. VISIBLE LIGHT CHARACTERISTICS OF LIGHT

2. Characteristics of light Light travels in a straight line (rectilinear propagation). Rectilinear propagation of light is responsible for the forming of shadows – light cannot travel around an object.

3. Characteristics of light Light is refelected from surfaces. The angle of incidence is exactly the same as the angle of reflection. Angle of incidence = angle of reflection

4. From a rough surface light will be reflected in a diffuse manner

5. See how light is reflected from concave and convex surfaces respectively Concave surface (left) and convex surface (right)

7. Your image is reflected in a mirror, but it is a virtual image The image in a mirror is:  Laterally inverted,  Upright,  As far behind the mirror as the object is in front of the mirror,  The same size as the object in the mirror and therefore it is  A virtual image.

8. Luminous and illuminated objects Some objects are luminous e.g. the sun and a light bulb. They produce/ give off light. The moon is illuminated; it reflects the light of the sun. Other planets are also illuminated; stars (suns) are luminous.

9. Objects/surfaces can be: 1. Transparent 2. Translucent 3. Opaque Can you see the difference? DEURSIGTIG

11. Breaking of light (Refraction) When light moves from one optic medium to another optic medium with a different optic density, refraction of the light will take place. Different optic mediums have different optic densities e.g. air has a lower optic density than water, which has a lower optic density than glass.

12. REFRACTION The speed and direction of light will change from one optic medium to the next. A change in direction is only visible when light strikes the dividing surface at an angle. AIR WATER

13. REFRACTION  When moving from a less dense optic medium to a more dense optic medium, the light will be bent (refracted) towards the normal.  When moving from a more to a less dense optic medium the light rays will be refracted away from the normal. AIR WATER

16. Refraction Refraction of light is the reason why we see an object under water in a different position from where it really is.

17. Refraction is responsible for a “mirage”

18. LENSES and the breaking of light

20. Refraction Light is refracted by the cornea of the eye, as well as the lens to focus the light rays on a specific point on the retina. A clear image is formed on the retina.

21. How are eye and sight problems addressed?

22. Laser procedure

23. Dispersion of light White light actually consists of seven colours: Red, orange, yellow, green, blue, indigo and violet. The refraction of light by a prism results in the dispersion of light.

24. Dispersion of light

29. Colour The colour of an object is caused by the colours of white light that are reflected:  Green leaves absorb all light but reflects green light.  Black objects absorb all light and reflect no light.  White objects absorb no light and reflect all the colours of white light.

30. FILTERS A filter allows a specific colour of light to be transmitted through a transparent surface e.g. stained glass.

31. FILTERS – STAINED GLASS WINDOWS

32. PRIMARY COLOURS: LIGHT AND PIGMENTS

33. LOOK AGAIN – PRIMARY COLOURS OF LIGHT

34. PRIMARY COLOURS OF PIGMENTS (paint)