1. Part 1 – Properties of Light
Light travels in straight lines:
Laser

2. NEW ENGLISH SCHOOL ,CHITALI STD=VIII DIV – B SUBJECT- SCIENCE SUBJECT TEACHER =MR .TAKE Y.B

3. Light travels VERY FAST – around 300,000 kilometres per second.
At this speed it can go around the world 8 times in one second.

4. Light travels much faster than sound. For example:
Thunder and lightning start at the same time, but we will see the lightning first.
2) When a starting pistol is fired we see the smoke first and then hear the bang.

5. We see things because they reflect light into our eyes:
Homework

6. Properties of Light summary
Light travels in straight lines
Light travels much faster than sound
We see things because they reflect light into our eyes
Shadows are formed when light is blocked by an object

7. Part 2 - Reflection Reflection from a mirror: Mirror Normal
Incident ray
Reflected ray
Angle of incidence
Angle of reflection
Mirror

8. Angle of incidence = Angle of reflection
The Law of Reflection
Angle of incidence = Angle of reflection
In other words, light gets reflected from a surface at ____ _____ angle it hits it.
The same !!!

9. Using mirrors
Two examples:
2) A car headlight
1) A periscope

10. Incident Ray & Reflected ray are on opposite sides of normal

11. Colour
White light is not a single colour; it is made up of a mixture of the seven colours of the rainbow.
We can demonstrate this by splitting white light with a prism:
This is how rainbows are formed: sunlight is “split up” by raindrops.

12. The angle of incidence & angle of reflection are of equal measure.

14. Types of reflection 1.Regular reflection 2.Irregular reflection

15. Regular reflection: 1.Reflection in which angle of incidence & angle of reflection is equal. 2. Incident ray & reflected ray are parallel to each other. 3.This type of reflection takes place through plane reflecting surfaces.

16. Irregular reflection 1.Reflection in which angle of incidence & angle of reflection is not equal. 2. Incident ray & reflected ray are not parallel to each other. 3.This type of reflection takes place through rough reflecting surfaces.