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The Electromagnetic Spectrum
Transcript of The Electromagnetic Spectrum
used the remote?
had a body part x-rayed?
Then YOU, have made use of the electromagnetic spectrum. What is the EM Spectrum? Let's take another look at that first picture...
check out that wavey line.... that's it!!! The electromagnetic spectrum is a wide range of electromagnetic waves, 7 categories, all different wavelengths and frequencies. Without the EM spectrum, our life as we know it could not exist... BOGO!!! These unique waves are a
"2-for-1" deal. They are two transverse waves put together. One of the waves vibrates the electric field, one of them vibrates the magnetic field. Let's take a closer look... Radio Waves Radio waves have the longest wavelength.
They are harmless.
These waves can be longer than a football field, or shorter than a football.
A radio station's call number is the wave's frequency.
You can't hear radio waves. Microwaves Microwave OVENS produce microwaves the WAVE.
Wavelength range = 1m - 1 cm
The shortest wavelengths (1 - 10cm) are used for cell communication.
Microwaves work by rocking the water molecules.
A man named Percy Spencer accidentally discovered the microwave. Percy had a chocolate bar in his shirt pocket. While working with microwaves, his chocolate suddenly melted! Infrared There are two types of Infrared.
Used by a remote control to "talk" to the tv.
Felt by you as heat. Anytime you feel heat from the sunshine, heater, fire etc.
Special cameras can "see" the heat, and take thermal images. They detect small changes in temperature, and assign each temperature a different color. Visible Light
This is the only portion of the spectrum we can see. (Actually, we can't see it. We can see it reflecting off objects.)
Within the EM spectrum, lies the visible spectrum.
Roy G. Biv
Each color has its own wavelength & frequency, so each bends at a different angle. Ultraviolet
Ultraviolet is another type of wave produced by the sun. (So far we have infrared, as heat, and visible light.
ULTRA VIOLET gets its name, because after violet in the visible spectrum, the wave with the next highest frequency is Ultraviolet.
Advantages & Uses include:
Sterilizing medical/dental/ piercing equipment
We use it to sterilize our safety glasses!!!
Humans have to have it in order to absorb vitamin D
United States Mints (producers our money) use UV sensitive stamps to verify its legitimacy
Water-treatment facilities use it to sterilize their waste
Allows plants to grow :)
These waves have such a high frequency, they are able to "wiggle" right in to our tiny cells. Once inside they "unzip" our DNA, which signals our body to make more cells with the altered DNA, which can cause tumors or cancerous cells.
Dangerous!!!! Very high frequency!!!
These tiny waves are used to take "pictures" of bones. The waves are sent into you, and pass right through your soft tissues, but get absorbed by your bones. When you look at an X-ray film, the black is the portion that has been "developed" by the rays; the white where no waves have penetrated.
Just like UV, these tiny waves are able to wiggle in and rearrange your DNA. Too much X-ray exposure can be harmful to your cells. Gamma
Highest frequency, shortest wavelength
Gamma waves are produced by radioactive atoms.
This takes place in nuclear reactors
And in supernova explosions in space
These waves are able to kill cells due to their tiny frequency and high energy. While these waves are dangerous, and can kill good cells, doctors use them to kill "bad" cells as well.