Transcript Chapter 4 - Tri-Valley Local Schools

Chapter 4
The Electromagnetic Spectrum
Part 2
Radio waves
• Includes FM, AM, radar and TV waves
• Used in many devices such as remote control
items, cell phones, wireless devices, etc.
Microwaves
• First used in radar, now used in
communication (wireless LAN
networks), and consumer use
(microwave ovens).
• medical applications in cancer
treatment (destroy tumors by
heating them).
• Most radio astronomy uses
microwaves
• “Active Denial System” – the
“Pain Ray”
Infrared Waves
• Infrared radiation is popularly known
as "heat"
• Used in heat lamps, de-icing
systems and thermomedic therapy.
• Missile guidance systems, short
range communication systems
• Weather satellites
Can be detected with special
devices such as night goggles
Weather satellites track weather systems using infrared.
Visible Light
• The portion of the electromagnetic spectrum
that human eyes can detect
• ROY G BIV (red, orange, yellow, green, blue,
indigo, violet)
• Red is the lowest frequency and violet is the
highest frequency
Visible Spectrum
We perceive electromagnetic energy having
wavelengths in the range 400-700 nm as visible light.
Ultraviolet
• Can cause skin cancer
and blindness in humans
• Used in tanning beds and
sterilizing equipment
• UV watermarks
• UV identification
Bee vision is very different from human vision, they
perceive colors we are simply incapable of seeing. Most
insects have light sensitive cells, or photoreceptors, that
are sensitive to ultraviolet light.
X-Rays
• Primarily used in
medicine.
X-Ray Scanners
X-Ray Diffraction
• The diffraction
of X-rays is
used to
disperse Xrays in a
spectrometer
and to
determine the
structure of
crystals or
molecules.
Gamma rays
• Highest energy and most
dangerous type of
radiation.
• Can cause cancer
through damage to DNA.
• Blocked from Earth’s
surface by atmosphere.
• Used in medicine and
irradiation.
Irradiation
Gamma Knife
Electromagnetic Waves
Star Finder Video:
Electromagnetic Spectrum
Homework
• Chapter 4: Worksheet 2