Electromagnetic Waves and the EM Spectrum Mrs. Molloy 6th Grade Science

Electromagnetic Waves… Do not need matter to transfer energy. Made by vibrating electric charges. Travel by transferring energy between electric and magnetic fields.

EM waves are transverse waves Move in a right angle to the direction of the energy Have crests and troughs Have the same properties as mechanical waves Wavelength Frequency Amplitude

Making Electromagnetic Waves When an electric charge vibrates, the electric field around it changes creating a changing magnetic field.

Making Electromagnetic Waves An EM wave can travel in all directions.

What is the speed of EM waves? EM waves travel 186,000 miles per second (speed of light) EM waves travel slowest in solids and fastest in gases. The speed of sound waves is only 760 miles per hour Mechanical waves travel fastest in solids and slowest in gases

Electromagnetic Spectrum The entire range of EM waves = electromagnetic spectrum. Different parts interact with matter in different ways. The ones humans can see are called visible light, a small part of the whole spectrum. Long wavelengths = low frequencies and short wavelengths = high frequencies

RADIO WAVES Have the longest wavelengths Lowest frequencies of all the electromagnetic waves. Examples: AM/FM radio, GPS, MRI

MICROWAVES Waves transfer energy to the water in the food causing them to vibrate which in turn transfers energy in the form of heat to the food.

INFRARED RAYS Infrared= Warm objects give off more heat energy than cool objects.

VISIBLE LIGHT EM waves we can see. Longest wavelength= red light Shortest wavelength= violet (purple) light

Carry more energy than visible light ULTRAVIOLET RAYS Carry more energy than visible light Used to kill bacteria. (Sterilization of equipment)

Too much UV radiation can cause skin caner Use sun block to protect against (UV rays) UV rays causes your skin to produce vitamin D (good for teeth and bones)

X- RAYS Carry a great amount of energy Can penetrate most matter. Bones and teeth absorb

Too much exposure can cause cancer X-Rays Too much exposure can cause cancer

GAMMA RAYS Shortest wavelength & highest frequency Carry the greatest amount of energy and penetrate the most.

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

Draw a line along the middle of your paper. Title your drawing The EM Spectrum Fold your paper in half. Label the middle Visible Light and then add the six other EM waves equal distances apart Label the wavelengths and add the “Wavelengths (meters)” label Draw and color seven pictures that show real world examples of the waves