1. 3.1 Electromagnetic Radiation
Name:____________
Date:_____________
Block:_____

2. This MRI image shows a cross section of a human abdomen.
Question
What technologies do you know uses invisible waves? Write down at least 5 answers.
This MRI image shows a cross section of a human abdomen.

3. Intro to EM Radiation:

4. Electromagnetic Radiation
Electromagnetic radiation is a form of energy.
Given off by different sources on Earth and in the universe
Most comes from the Sun
Some types are harmful, and other types are essential to survival of life on Earth

5. Electromagnetic Radiation
Seven different types of electromagnetic radiation:
Radio wave
Microwave
Infrared
Visible light
Ultraviolet
X-ray
Gamma-ray
Radio waves – radio broadcasts
Microwaves – cooking, mobile and satellite communications, WiFi
Infrared – heat radiation – everything emits infrared. Remote controls, heaters, infrared goggles
Visible - light that allows humans to see
UV – sterilization, banks to detect counterfeit money, tanning beds - too much exposure leads to skin cancer
X-rays – to see internal structures
Gamma – produced by energy changes in nuclei of atoms. New use in cancer cells…
Image of the Sun taken with an ultraviolet telescope.

6. Think of a Mnemonic R ___________________________
V ___________________________
U ___________________________
X ___________________________
G ___________________________

7. Electromagnetic Spectrum
The range from longest wavelength to shortest wavelength is called the Electromagnetic Spectrum
High Energy
Low Energy

8. Electromagnetic Spectrum

9. Sources of Electromagnetic Radiation
There are many different sources of electromagnetic radiation:
Some sources are artificial such as cell phones, light bulbs
Some sources are from living organisms such as humans
The Sun gives off all types of electromagnetic radiation.
The large amount of energy released by the Sun supports life on Earth.
The Sun is a source of all types of electromagnetic radiation.

10. Nuclear Fusion

11. Electromagnetic radiation enhances how we sense our world.
Luminol is sprayed at a crime scene to test for blood
When luminol mixes with iron, it emits visible light
You are an electromagnetic radiation detector.
Skin: special cells sense infrared radiation, and send a message to your brain that is interpreted as heat
Eyes: sense visible light to see brightness, objects, and colour
Electromagnetic radiation and technology lets us “see” in a new way
This image of a supernova (exploding star) combines data from telescopes sensing different kinds of electromagnetic radiation

12. Figure 3.1: Electromagnetic radiation is often discussed online and covered by the news.

13. Figure 3.1: Electromagnetic radiation is often discussed online and covered by the news.

14. Blue Light

15. Figure 3.1: Electromagnetic radiation is often discussed online and covered by the news.

16. X Rays

17. Discussion Questions
Why do you think sunglasses have special lenses that filter out ultraviolet light?
Why might you want to limit the amount of time you spend in front of an electronic screen at night?
1.     Since ultraviolet radiation can cause eye damage, it makes sense for sunglasses to have special lenses to filter out the radiation.
2.     Blue light given off by electronic screens has been linked to sleep problems.

18. Electromagnetic Spectrum

19. Radio Waves Has the longest wavelength and lowest energy
Communication systems (fire, police, emergency systems) and radio stations generate radio waves
They send signals to radio receivers that convert them into sound
Used in MRI’s

20. Microwaves Cell phones are a source of microwaves.
Microwaves carry information from the cell phone to nearby cell phone tower
Microwave ovens use microwaves
Cell phone towers create microwaves that carry information from cell phone to cell phone.

21. Infrared Radiation
All objects, including you, give off infrared radiation.
Referred to as heat radiation
As objects get hotter, they give off more infrared radiation that is sensed as heat
Used every day in remote controls, by computers to read CDs and DVDs, heaters, infrared goggles

22. Visible Light Visible light is a wave that we can see
The visible spectrum includes seven colours: ROY G BIV
Do you remember the colours?
red, orange, yellow, green, blue, indigo, violet
Together these 7 colors are known as the visible spectrum.
Each color emitted have different wavelengths
Some chemical reactions give off visible light.

23. Visible Light
Of the waves that make up visible light, red has the longest wavelength and lowest energy.
Violet has the shortest wavelength and highest energy.

24. Ultraviolet
Coming from the sun, ultraviolet rays strike your skin and enable it to make vitamin D
Often used for sterilization
Solving crimes
Tanning beds
Overexposure can cause sunburns and skin cancer

25. X-Rays
X-rays are produced in an x-ray tube and can be used to create images of teeth and bones
Overexposure can be dangerous

26. Gamma Rays
Gamma rays are produced by unstable nuclei of certain atoms.
Atoms with unstable nuclei are called radioisotopes.
Radioisotopes have too much energy
To become stable, they give off energy in different forms, including gamma rays
Gamma rays are highest in energy and have the shortest wavelengths
Focused burst of gamma rays are used in radiation therapy to kill cancer cells

27. Radioisotopes: A Source of Gamma Rays
Iodine-131 is a radioisotope that gives off gamma rays
It is used to treat thyroid cancer
When a patient swallows it, it will go to the thyroid gland to kill the cancer cells
A gamma camera image of a thyroid gland injected with radioactive iodine

28. Discussion Questions a halogen light bulb the Sun iodine-131 you
What type or types of electromagnetic radiation are given of by the following sources?
a halogen light bulb
the Sun
iodine-131
you