1. Properties and Characteristics
EM NOTES
Properties and Characteristics

2. What do we know about EM waves in general?
They are ALL Energy—Radiation!
Non-mechanical Transverse waves
They do not need a medium—travel in space!!
Have crests/troughs
They all travel at the speed of light
(300,000 km/sec) in space!
Fastest: Space…air…water…solid: slowest
Most are not visible by the human eye!

3. How are EM waves Different?

4. How are EM waves Different?
They have different
Frequencies
Wavelengths
Amounts of energy
These characteristics impact some of their properties and behavior!

5. ROY G. BIV One EM Example: The EM wave we can detect (see)
Visible Light
The EM wave we can detect (see)
It is WHITE = blend of all colors
ROY G. BIV
(Red, Orange, Yellow, Green, Blue, Indigo, Violet)
Different due to wavelength and frequency

6. Wave Behavior
EM waves behave a certain way when they hit a material. They may possibly…
Reflect—bounce off
Absorb – held within = heat
Transmit- travel through

7. Reflection
Waves bounce (reflect) off of a surface at the same angle that they hit the surface at.
Mirror

8. Reflection
Examples: MIRRORS!!!
Four eyed mutant bipeds

9. Reflection Sound can be reflected also = Echo
Other real-life examples…
A submarine periscope
Games dealing with angles!
Ping pong, basketball, pool
Sound can be reflected also = Echo

10. Absorption & Reflection
Why do we see certain colors?
Different frequencies of light are “absorbed” or “reflected”
What we see = reflected to our eyes

11. Absorption & Reflection
Red Truck is red because…
Truck absorbs all light waves except red
red is reflected back to our eyes
Do you wear a white or black shirt in the summer?
If all light is absorbed = BLACK = Hotter
If all light is reflected = WHITE = Cooler

12. Absorption & Reflection
Black clothes absorb more light energy = HEAT!!!
Avoid black in summers
Wear black in winters

13. Waves Transmitted Waves travel through an object/material
Not reflected or absorbed
What two things will determine if a wave transmits through?
The waves energy and The medium
When they travel through they may…
1. Refract OR 2. Disperse or Diffract

14. Refraction waves change speeds as they move through different mediums.
Changing speeds causes Waves To Bend!
Wave going in
(Water)
Wave refracted

15. Refraction
Example:
Where is the fish actually at if you are fishing using the diagram? WHY?

16. Refraction
Example:
Where is the fish actually at if you are fishing using the diagram? WHY?
The fish is actually further than what the man will see.
Actual fish

17. Dispersion / Diffraction
When white light passes through a prism or slit it bends causing the colors to separate so you can see them.
What causes a rainbow?
raindrops cause the light to disperse