waves of the electromagnetic spectrum eq: what is the electromagnetic spectrum?
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Waves of the Electromagnetic Spectrum
EQ: What is the electromagnetic spectrum?
Vocabulary
• Electromagnetic Spectrum– Range of electromagnetic waves when they
are ordered by increasing frequency– Remember all EMW travel at the same speed,
but they have different wavelengths and frequencies
• As the wavelength decreases, the frequency increases
• The amount of energy carried by EMW increases as its frequency increases.
EQ: What is the electromagnetic
spectrum?
Electromagnetic Spectrum
• Made up of 7 different types of waves
EQ: What is the electromagnetic
spectrum?
Radio Waves - EMW with longest wavelengths and lowest frequencies
Can travel through a vacuum but most of our radio waves travel through air.
1. Antennas pick up radio waves from the air.
2. Then the radio waves go to the wires in your radio
3. The radio converts the EMW into sound that comes out your radio
EQ: What is the electromagnetic spectrum?
Microwaves – shorter wavelengths and higher frequency
Microwave ovens and cell phones most common use
EQ: What is the electromagnetic
spectrum?
Cell Phones–a transmitter and a
receiver
–cell phones depend on an overlapping network of cells, or areas of land several kilometers in diameter
–cell tower in the center of “cell” receives and sends microwaves
EQ: What is the electromagnetic spectrum?
Radar – shortest wavelength microwaves
• Stands for radio detection and ranging
• Used to locate objects
• Use radio waves and the Doppler effect to calculate speed of vehicles
EQ: What is the electromagnetic
spectrum?
Infrared Waves
Give off heat – heat lamp, electric stove, toaster. Humans can sense it
Have shorter wavelengths and higher frequencies than radio waves
Infra means below – below red on the color spectrum
EQ: What is the electromagnetic spectrum?
Infrared Waves
Thermogram – pictures taken by infrared camera. Shows regions with different temperatures with different colors– Used to detect motion of
clouds, growth of plants EQ: What is the electromagnetic
spectrum?
Visible Light
• The light we can see
• Longest wavelength of visible light are red, shortest is purple
• Rainbow or prism refracts, or bends the light waves to produce different colors
EQ: What is the electromagnetic
spectrum?
Visible Light
• Waves
EQ: What is the electromagnetic
spectrum?
Ultraviolet Rays
• UV rays
• Ultra is Latin for beyond, so these waves are just beyond the color violet
• Carry more energy than visible light because they travel at a higher frequency
EQ: What is the electromagnetic
spectrum?
Ultraviolet Waves
UV lamps used to kill bacteriaUV waves help produce vitamin D in the body, cause sunburnHelp newborns who have jaundice
EQ: What is the electromagnetic spectrum?
X - Rays
• Carry more energy than UV rays because of their higher frequency
• Can penetrate most matter with the exception of bone and lead. These are too dense
EQ: What is the electromagnetic
spectrum?
Gamma Rays
• Shortest wavelength and highest frequency
• Used in radiation therapy to kill cancer cells
• Examine body’s internal structure
Supernova
EQ: What is the electromagnetic spectrum?
Class Work and Homework
• Fill In – What did I learn– Confused– Say
– Read pages 79– 86– Electromagnetic spectrum jumble– questions 1-6 and page 87 “Are cell phones
harmful?”
EQ: What is the electromagnetic
spectrum?
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