Light can travel through space in straight lines and comes in different forms, including visible light. There are various ways that light can be produced, including incandescence from heated objects, electric discharge through gases, and chemiluminescence from chemical reactions. Lasers produce coherent electromagnetic waves of the same wavelength and phase which travel in parallel, and are used in applications like manufacturing, astronomy, and entertainment due to their precision and focus.

2. Light travels in straight lines

3. Unlike heat or electricity, light can travel through space.
Light is an electromagentic wave.

4. The electromagnetic spectrum

5. Visible light

6. Visible light
INCREASING ENERGY

7. Wavelength and colour

8. Seeing colour

9. Pinhole camera

10. How is light produced?
Luminous source
Produces its own light
Vs. Non-luminous source
Does not produce its own light

11. 1) Light from incandescence
Producing
light as a
result of
high
temperature
Heated
tungsten wire
glows

12. 2) Light from electric discharge
Producing light by passing an electric current
through a gas
LIGHTNING
NEON LIGHTS

13. 3) Light from phosphoresence
Producing light by the absorption of UV light
resulting in the emission of visible light over an
extended period of time

14. 4) Light from fluorescence
Producing light by the absorption of UV light
resulting in the immediate emission of visible light

15. 4) Light from fluorescence

16. 4) Light from fluorescence

17. 5) Light from chemiluminescence
Producing light as the result of a chemical reaction
with little to no heat produced

18. 5) Light from chemiluminescence
-2 chemicals, 1 in a narrow
small glass vial
-Bending the stick breaks
the vial, causing
chemicals to mix
-Chemical reaction
produces visible light

19. 5) Light from chemiluminescence
APPLICATIONS:
-Hazardous environments
where sparks can be
dangerous
-Underwater diving
-Camping
-Law enforcement
-Military
-Entertainment (concerts,
dance halls, amusement
parks)

20. 6) Light from bioluminescence
Light produced in living organisms as the result
of a chemical reaction with little or no heat
produced

21. 6) Light from bioluminescence

22. 6) Light from bioluminescence

23. 7) Light from triboluminesence
Light produced by friction as a result of scratching,
crushing, or rubbing certain crystals

24. 8) Light from a Light-Emitting Diode (LED)
Light produced by an electric current flowing in
semiconductors
Differs from incandescent bulbs
-Does not produce much heat
-Does not require a filament
-More energy efficient
Semiconductor = material that allows an electric current to
flow in only one direction

25. 8) Light from a Light-Emitting Diode (LED)

26. LASERS
LASER = Light Amplification by Stimulated
Emission of Radiation

27. Lasers Vs. Incandescent bulbs
Incandescent bulbs emit electromagnetic waves of
many different energy levels

28. Lasers Vs. Incandescent bulbs
A laser produces electromagnetic waves of exactly
the same energy level
In lasers, electromagnetic waves
1)Travel in exactly the same direction
2)Are exactly in unison

30. APPLICATIONS OF LASERS
-manufacturing
-astronomy*
-research
-entertainment
-military
-media technology
*Earth-moon distance measured to be 385 000km with an accuracy of 3cm!

31. APPLICATIONS OF LASERS

32. APPLICATIONS OF LASERS

33. Land – reflects laser light back into the head
Pit – scatters light in all directions
Reflected light then converted into 0’s and 1’s (binary data).