1. Studio Magic
Lesson Four : Light

2. Expected Learning
To be able to explain how light is created, and the way it travels.

3. Key Words
Electron
Electromagnetic Wave
Luminescent
Reflection

4. Electromagnetic Radiation
Light is a form of Electromagnetic Radiation (EMR).
Other types of EMR include Infrared, Ultraviolet, Microwaves and Radio waves.
EMR is made when an electric charge vibrates and creates EM waves that move away from the charge, like ripples in a pond.

5. Example
Click here to play with an example of a charge making EM waves.
Move the charge around to see how it makes waves that move out around it.

6. Luminescent Objects that give off light are called Luminescent.
In these objects charges are being vibrated by heat, electricity, or chemical reactions to create light.

7. Task One:
Make a list of as many Luminescent objects as you can think of.
Sort them into three groups – Heat, Electricity and Chemical reactions , based on how the light is made – you must have at least one in each group.

8. Light waves don’t need particles to transfer energy …
… so light can travel through any medium – solid, liquid, gas – or even empty space!
Explain

9. Light always travels in straight lines.
Explain
SS2

10. Reflection
Light can “bounce off” or reflect from solids , or from boundary's between materials.
Most objects are quite rough when you look closely at them, so light reflects in all directions from them.

11. Reflection
Some objects, such as mirrors, are very smooth. Light which hits these objects reflects at the same angle it hits.

12. Mirrors reflect light. The incident ray travels towards the mirror.
The reflected ray leaves the mirror at the same angle.
Explain

13. The speed of light
Light waves travel VERY fast. In space they travel 300,000 km every second.
As far as we know – nothing can travel faster than light.

14. Task Two:
Investigate what a LIGHT YEAR is (write answers in your book):
How is a light year defined?
Write down how many kilometres a light year is (Warning – Large number ahead)?

15. Test your Knowledge.. True or false – these are examples of EMR…
1. Sound
2. Heat rays
3. Light
4. Electric currents
5. Mobile Phone signals
6. X-rays

16. Test your Knowledge..
Which diagram shows a Diffuse reflection?
A B