The Electromagnetic Spectrum

By: Christopher Wainwright Aaron & Tom Baroni

What is it?

• The electromagnetic spectrum is the complete spectrum or continuum of light including radio waves, infrared, visible light, ultraviolet light, X-rays and gamma rays

• An electromagnetic wave consists of electric and magnetic fields which vibrates thus making waves.

The Electromagnetic Spectrum

By: Christopher Wainwright Aaron & Tom Baroni

Nature of Electromagnetic Waves

• They are Transverse waves without a medium. (They can travel through empty space)

• They travel as vibrations in electrical and magnetic fields.

• Have some magnetic and some electrical properties to them.

• Speed of electromagnetic waves = 300,000,000 meters/second (Takes light 8 minutes to move from the sun to earth {150 million miles} at this speed.)

Waves or Particles• Electromagnetic radiation has properties of waves but

also can be thought of as a stream of particles.• Example: Light• Light as a wave: Light behaves as a transverse wave

which we can filter using polarized lenses.

• Light as particles (photons)

• When directed at a substance light can knock electrons off of a substance (Photoelectric effect)

Wavelength, Frequency and Energy

• Since all light travels at the same speed, wavelength and frequency have an indirect relationship.

• Light with a short wavelength will have a high frequency and light with a long wavelength will have a low frequency.

• Light with short wavelengths has high energy and long wavelength has low energy

RADIO WAVES• A. Have the longest wavelengths and lowest

frequencies of all the electromagnetic waves.• B. A radio picks up radio waves through an antenna and

converts it to sound waves.• C. Each radio station in an area broadcasts at a

different frequency. # on radio dial tells frequency.• D. MRI (MAGNETIC RESONACE IMAGING)– Uses Short wave radio waves with a magnet to create an

image

Bands of Radio/TV/Microwaves

Microwaves

• Longer than radio, shorter than light and infrared

• Wavelength 1 x 10 - 4 m to 1 x 10-1 m

• First used in radar, now used in communication, medicine and consumer use (microwave ovens)

Infrared waves

• Invisible electromagnetic waves that are detected as heat

• Can be detected with special devices such as night goggles

• Used in heat lamps• Higher energy than microwaves

but lower than visible light

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

Ultraviolet waves

• Higher energy than light waves• Can cause skin cancer and blindness in

humans• Used in tanning beds and sterilizing

equipment

The Electromagnetic Spectrum

X-Rays

• High energy waves• First discovered by

Roentgen • Used in medicine, industry

and astronomy• Can cause cancer

GAMMA RAYS

• Shorter wavelength and higher frequency than X-rays

• Carry the greatest amount of energy and penetrate the most.

• Used in radiation treatment to kill cancer cells.• Can be very harmful if not used correctly.

Test Time

• 1. What is the relationship between frequency and wavelength?

• 2. What is meant by ‘spectrum’?

• 3. What does ROY G BIV mean?

Now, let’s really think

• 4. Can you actually see x-rays?– Support your answer.

• 5. Which color is more energetic, red or yellow?

• 6. Which type of wave travels faster, gamma or radio?

• 7. Why are microwaves more dangerous than radio waves?

Answers• 1. Frequency and wavelength are properties of waves and since speed is

constant for em waves, as frequency increases, wavelength decreases.• 2. Spectrum is a continuum of all electromagnetic waves• 3, ROY G BIV is the difference colors of the visible light in order of longest

wavelength to shortest wavelength.• 4. X-rays can not be seen, only the waves in the visible light portion are

visible.• 5. Yellow is higher energy than red because it has a shorter wavelength

and higher frequency.• 6. Both travel at the same speed, 300,000 km/s (all em waves travel at the

same speed)• 7. Microwaves have a higher frequency than radio and carry more energy.

References

• en.wikipedia.org/wiki/Electromagnetic_spectrum

• imagine.gsfc.nasa.gov/docs/science/know.../emspectrum.html

• hyperphysics.phy-astr.gsu.edu• science.hq.nasa.gov/kids/imagers/ems/ems.html

The Electromagnetic spectrum

By Anna Proctor & Lindsey Ferris

What the heck is the electromagnetic spectrum?!

The Electromagnetic Spectrum is the range of all possible frequencies of electromagnetic radiation, or waves.

It distributes or absorbs radiation through different objects.

The full set of waves that can travel through space; includes not only visible light but short waves.

How colors are used to show the level of frequencies.

A special device is used to control the movement of electromagnetic waves. These waveguides are typically metal-based lines pitched at microwave frequencies to link connections between antennas and receivers. It’s a one-way channel that picks up signals and an attenuator keeps the signals strength at a constant.

Different types of radiation Radio waves are the

longest wavelength in the electromagnetic spectrum.

Infra red light is associated with heat and things that give off heat. Ex: TV remote controls.

Visible light is the only thing our eyes can detect in the Electromagnetic spectrum.

Ultra-violet light is made by special lamps which in other words, replaces to sun. Ex: tanning beds.

More types of radiation

Microwaves are transmitted through mobile phones.

Gamma rays are the highest frequency waves

X-rays are waves used to inspect luggage at an airport or to see through human skin to their bones.

Measurements of the electromagnetic spectrum.

The tiniest waves are measured in angstroms, a

unit of length equal to one hundred-millionth of a centimeter.

Waves of visible light are measured in nanometers (nm).

While waves in infrared to radio are measured in more familiar meters.

How else can wavelengths be measured?

The electromagnetic spectrum can be expressed in terms of energy, wavelength, or frequency.

Visible wavelengths!Are the only electromagnetic waves we can see. We see these waves as the colors of the rainbow. Each color has a different wavelength. Red has the longest wavelength and violet has the shortest wavelength. When all the waves are seen together, they make white light.

Each color of the rainbow corresponds to a different wavelength of the electromagnetic spectrum.

THIS CHART SHOWS ALL THE DIFFERENT COLORS AND HOW THEY ARE IN RELATION TO ONE ANOTHER.

Color Charts

A closer look at colors.

This a picture at normal size, then blown up 200, 400 and 800 times. Most pictures in magazine are made up of colored dots.

A magazine printing press usually can only print four colors: Cyan, Magenta, Yellow, and Black. Our eyes and brain put colors together from the colored dots.

QUIZ TIMEEE. QUIZ TIMEEE.

Sources.http://www.learner.org/teacherslab/science/

light/color/dots/index.html

http://imagine.gsfc.nasa.gov/docs/science/know_l2/emspectrum.html

http://science.hq.nasa.gov/kids/imagers/ems/ems.html

http://home.clara.net/darvill/emag/index.htm