Electromagnetic Spectrum. Waves are everywhere! Wave – Disturbance that moves through space –...

Electromagnetic Spectrum

Waves are everywhere!• Wave– Disturbance that moves through space– Takes energy/information and moves it from one

location to another

Waves come in 2 Types

• Transverse– String moving up and

down– Wave moving

perpendicular• Looks like a T on its

side

• Longitudinal– Moves in the direction

of the motion (back and forth)

– Can happen in water or air

Wave Properties• Wavelength– Distance from crest to crest (same as trough to

trough)• Crest– Top of wave

• Trough– Bottom of wave

• Amplitude– Size / Height of the wave– Increase in amplitude = increase in energy

Properties of Waves• Amplitude– Increased amplitude = Increased energy– Low amplitude = Quieter– High amplitude = Louder

• Frequency– Number of waves that pass per second (Hertz)– Low frequency = Low pitch– High frequency = High pitch

What happens when two waves hit?

• They cancel each other out or they add to each other

Additional Wave Properties• What happens as waves move from one

property to another–Absorbed–Reflection• Hits a surface and it bounces off

–Refraction• Wave is being bent• Happens when it hits water

–Diffraction• Waves bend

Electromagnetic Spectrum

• Light Waves–Radio Waves (Larger wavelength, less energy)

–Microwaves– Infrared Waves–Visible Light–Ultraviolet Radiation–X-Ray Waves–Gamma Rays (Shorter wavelength, more energy)

Radio Waves

• Longest Wavelengths– Length of a football field

• Given off by stars– Can provide information about our solar system

• Used mainly to communicate– AM and FM Radios have different frequencies– Police Radios also are on their own frequency

Microwaves

• Used in weather maps• Used in microwaves to cook food• Used in radar detectors (speed)

Infrared Radiation• Makes objects feel warmer• Given off by the sun and

other stars• Used in remote controls• Used in thermal imaging• Used by weather maps

Visible Light

• White light and colors• Seen in a rainbow• The one color we see is the only color that’s

not absorbed

Ultraviolet Radiation

• Given off by the sun (and certain lamps)• Used when tanning• Can used to sterilize equipment• Can damage your eyes and skin

X-Ray Waves• Very high frequency = lots of energy• Given off by stars and x-ray machines• Pass through soft tissues but not as easily

through bones• Used in airport security to see inside luggage• Very harmful to cells

Gamma Rays• Given off by stars and radioactive substances• Extremely high frequency• Lots of energy• Passes through most materials• Used to kill cancer cells

Math Problems

• V = f (ʎ)– Velocity (Speed) = Frequency * Wavelength–m/s = Hz * m

Math Problems

• A tsunami has a wavelength of 210,000m and a frequency of 0.00067Hz. Calculate the speed of the wave– V = 0.00067 Hz * 210,000m – V = 1407 m/s