Science 4.3 Notes
Terms in this set (43)
What spectrum is the visible spectrum a part of? (pg 152)
The electromagnetic spectrum
Radio waves and infrared radiation have... (3 things) ... than visible light. (pg 152)
Longer wavelengths, lower frequencies, and less energy
Ultraviolet light, X rays, and gamma rays all have... (3 things) ... than visible light. (pg 152)
Shorter wavelengths, higher frequencies, and more energy
What does each region of the invisible electromagnetic spectrum have? (pg 152)
Special properties to make it useful in some sort of imaging technology
What is radiation? (pg 153)
When energy spreads out (or radiates) in all different directions
What type of energy is energy that travels by radiation? (pg 153)
The sun radiates both ______ energy, which we call light, and ______ energy. (pg 153)
What fields vibrate in a light wave? (pg 154)
Electrical and magnetic fields
Why is light classified as electromagnetic radiation? (pg 154)
Because electric and magnetic fields vibrate in a light wave
How are electromagnetic waves described/categorized? (pg 154)
Based on wavelength and frequency
From longest to shortest wavelength, what types of waves exist on the electromagnetic spectrum? (pg 154)
Radio waves, microwaves, infrared waves, visible light, ultraviolet waves, x-rays, gamma rays
Most waves on the electromagnetic spectrum are...? (pg 154)
What are radio waves? (pg 154)
Radio waves are a type of electromagnetic
radiation that have the longest wavelength
and lowest energy and frequency compared
to all other types.
What are can radio waves be used for? (pg 154, 155)
Radio and television broadcasting, magnetic resonance imaging (MRI), etc
Microwaves and radar are types of... (pg 154)
How does magnetic resonance imaging (MRI) work? (pg 155)
In MRI scans, a patient lies in a large cylinder equipped with a powerful magnet, a radio wave emitter, and a radio wave detector. Particles in the bones and soft tissues act like tiny magnets, so when the MRI machine causes the orientation of the particles to flip, they produce radio waves. The energy is picked up by the radio receiver and used to create a map of the different tissues.
What are microwaves? (pg 155)
A type of radio wave
Microwaves have the ____ wavelength and the ____ frequency of all the radio waves. (pg 155)
How do microwave ovens work? (pg 155)
Microwave ovens use a specific wavelength or frequency of microwave that is strongly absorbed by water particles. When the water particles in the food absorb microwaves, they vibrate quickly and get hot. Only foods that have water particles in them can be heated using microwaves.
What can microwaves be used for? (pg 155)
Telecommunication via satellites
What does radar stand for? (pg 156)
RAdio Detecting And Ranging
What is radar? (pg 156)
A shorter wavelength microwave
How does radar work? (pg 156)
Microwaves are beamed out through the air, and the waves that reflect back from an object it comes in contact with can show the location and speed of the object.
What can radar be used for? (pg 156)
Tracking the movement of automobiles,
aircraft, watercraft, and spacecraft. Weather forecasting
What is the RADARSAT? (pg 156)
RADARSAT is a Canadian satellite that sweeps the ground below
with radio waves
What are infrared waves? (pg 157)
Infrared waves are a type of electromagnetic radiation that, relative to light, has a longer wavelength and lower energy and frequency.
How can infrared waves be used? (pg 157)
Television remotes, reading CD-ROMs on a computer, heat lamps, etc
What else is infrared radiation also referred to as? (pg 157)
Why do all objects emit some infrared waves? (pg 157)
Because all objects contain some heat energy
____ objects emit more infrared waves than ____ objects. (pg 157)
What does "infrared" mean? (pg 157)
What do wavelengths that are shorter than visible light carry? (pg 158)
What does "ultraviolet" mean? (pg 158)
What are ultraviolet waves? (pg 158)
Ultraviolet waves are a type of electromagnetic radiation that, relative to light, has a shorter wavelength and higher energy and frequency. They are very energetic.
What does ultraviolet radiation do? (pg 158)
Enables your body to make Vitamin D, which you need for healthy bones and teeth
What can an overexposure to ultraviolet radiation do? (pg 158)
Sunburns, skin cancer, damage to the surface of the eye
What can UV rays be used for, other than in sunlight? (pg 159)
Investigating crime scenes (fluorescent materials absorb ultraviolet waves and emit the energy as visible light), and killing bacteria in food, water, and medical supplies
What are X rays? (pg 159)
X rays are a type of electromagnetic radiation that have a much shorter wavelength and higher energy and frequency than ultraviolet waves.
Who discovered X rays and when? (pg 159)
Wilhelm Roentgen, a German physicist,
discovered X rays in 1895.
What are X rays commonly used for? (pg 159, 160)
Photographing teeth and bones, airport security, photographing the insides of machines, inspection for cracks in high performance jet engines, etc
What are gamma rays? (pg 160)
Gamma rays are the highest energy and frequency and shortest wavelength portion of the electromagnetic spectrum.
Where do gamma rays come from? (pg 160)
Gamma rays result from nuclear reactions and are produced by the hottest regions of the universe.
What are gamma rays used for? (pg 160)
Focussed bursts of gamma rays are used in radiation therapy to kill cancer cells.