1. Electromagnetic Spectrum

2. What are some differences you notice about these images
What are some differences you notice about these images? Why would having these different images be important to the study of the universe?

3. Light Light Energy - Energy that travels in the form of waves.
Example: Sunlight

4. Light Light - a transfer of energy that creates a visual sensation
Light is a transverse wave

5. Light
Light does not need a medium to travel

6. Light Frequency - the number of waves passing a point per second
Units: Hertz (Hz)
Frequency describes the color/type of light
HIGH frequency = Ex. UV Light Waves
LOW frequency = Ex. Radio Waves

7. Light
Let’s look at the relationship between wavelength, frequency, and energy, as it applies to waves.

8. Light
Light belongs to a larger category of waves called the electromagnetic spectrum.
Electromagnetic spectrum - the full range of visible and invisible waves.

9. What is the Electromagnetic Spectrum?
Professor Dave Explains...

10. Light The electromagnetic spectrum includes:
Radio waves
Microwaves
Infrared waves (IR)
Visible light
Ultraviolet waves (UV)
X-Rays
Gamma rays
All waves travel 300,000 km/s = SPEED OF LIGHT

11. Electromagnetic Spectrum
Visible
Light
Radio
Microwaves
Infrared
(IR)
Ultraviolet
(UV)
X-Ray
Gamma
LONG
Wavelength
Frequency
Energy
SHORT
Wavelength
Frequency
Energy
LOW
HIGH R V O I
LOW Y G B
HIGH

12. Electromagnetic Spectrum
Radio Waves - longest wavelength and lowest frequency and energy
used in radio and TV, microwave ovens, and radar.
Cell phones

13. Electromagnetic Spectrum
Microwaves - slightly shorter wavelength than radio, slightly higher frequency/energy
Cooking and reheating food

14. Electromagnetic Spectrum
Infrared Light (IR) - source of heat and used to discover heat differences
Warming lamps
Thermograms

15. Electromagnetic Spectrum
Visible Light - only light visible to humans
Color (ROYGBIV)

16. Electromagnetic Spectrum
Ultraviolet Light - higher frequency than violet
Sunlight (source of Vitamin D)
Excessive exposure damages skin
Can disinfect air/bacteria

17. Electromagnetic Spectrum
X-Rays - makes pictures of the inside of solid objects
X-Ray technology

18. Electromagnetic Spectrum
Gamma Rays - high energy waves with the greatest penetrating ability of all waves.
Radiation therapy