1. Electromagnetic Radiation and Light
7th Grade Science
LaVilla School of the Arts

2. By the end of this lesson, you should be able to…
Identify, compare and contrast the types of EM radiation from the Sun
Know common uses and applications of the EM spectrum
Know the order of frequencies and wavelengths in the EM spectrum
Interpret the relationship between frequency and wavelength in the EM spectrum
Describe and give examples of light reflection, refraction and absorption
Know that wavelength is related to the amount of energy carried.

3. Lets recap what EM waves are…
They do NOT need a medium to travel
They only travel through transverse waves
The Sun is a major source of EM waves

4. What is radiation? Radiation is the transfer of energy as EM waves.
EM waves can have a variety of different frequencies and wavelengths. There are 7 sources of EM waves that are part of the EM spectrum:

5. ULTRAVIOLET LIGHT (UV)
What is the EM spectrum?
There are 7 sources of EM waves that are part of the EM spectrum:
RADIO WAVES
MICROWAVES
INFRARED LIGHT
VISIBLE LIGHT
ULTRAVIOLET LIGHT (UV)
GAMMA RAYS

6. Types of EM radiation MAKE A 2 COLUMN CHART LIKE THIS:
TYPE OF EM RADIATION
USES
RADIOWAVES
MICROWAVES
INFRARED LIGHT
VISIBLE LIGHT
UV LIGHT
X-RAYS
GAMMA RAYS

8. Types of EM radiation ANSWER KEY: TYPE OF EM RADIATION USES RADIOWAVES
Radio and TV
MICROWAVES
Cooking, radar, TV, other
INFRARED LIGHT
HEAT from sun, fires, radiators
VISIBLE LIGHT
Things can be seen
UV LIGHT
Absorbed by skin, florescent tubes
X-RAYS
See inside of bodies
GAMMA RAYS
Medical treatment (kills cells)

9. What about the SUN?
The Sun gives off mostly visible light, but gives off radiation in ALL areas of the EM spectrum!

10. How much is too much radiation?
Answer…. The frequency or the wave.
The HIGHER the frequency, the MORE ENERGY that wave has = more dangerous.
Like UV rays and gamma rays
Gamma rays kill cancer cells
The LOWER is frequency, the LESS ENERGY that wave has = less dangerous.
like radio waves, microwave, infrared, visible light

11. ROYGBIV…. What is it?
Red
Orange
Yellow
Green
Blue
Indigo
Violet

12. The longest wavelength = RED The shortest wavelength = VIOLET
What determines the color of light? FREQUENCY!
The longest wavelength = RED
The shortest wavelength = VIOLET

13. How do we see white or black?
When we see WHITE… ALL colors of ROYGBIV are reflected
When we see BLACK… ALL colors of ROYBGIV are absorbed