Electromagnetic Waves Objectives

1. Know the names of each type of wave.2. Know the order of the waves according to the

wavelength/frequency3. Know what each of the waves are used for 4. Know that all EM waves can travel through

matter and empty space5. Know that all of the EM waves travel at the

speed of light

Electromagnetic WavesElectromagnetic waves (radiant energy) – waves that can travel through empty space and through matter.

All EM waves travel at the speed of light.

2-10-14

All matter produces EM waves, and therefore, radiant energy.

Electromagnetic Spectrum

waveLight

• Longer wavelengths

• Lower frequencies

• Lower energy

• Shorter wavelengths

• Higher frequencies

• Higher energy

Roman Men Invented Very Unusual X-Ray Guns

Electromagnetic Spectrum

waveLight

• Longer wavelengths

• Lower frequencies

• Lower energy

• Higher frequencies

• Higher energy

-Used for communi-cation-Radio stations-Television stations

-Used for communic-ation-Can carry more info than radiowaves-Radar guns-GPS-Cellphones-Microwaves

-Vibrating molecules in all matter give off infrared waves-Thermal cameras detect infrared waves

-Waves carry enough energy to cause chemical reactions-Causes sunburns, possibly skin cancer-UV Wand - dries adhesives-Tanning Beds

-Can pass through skin and muscles, but not bone-Airport Scanners

-Produced when the nucleus of an atom breaks apart or changes-PET scans-Nuclear reactions-Destroys diseased cells

• Used for communication–Radio stations–Television stations

Radiowaves

Microwaves• Used for communication• Can carry more info than

radiowaves– Radar guns– GPS (Global Positioning

Systems)– Cellphones– Microwaves

Infrared Radiation• Vibrating molecules in all matter give off

infrared waves–Thermal cameras detect infrared waves

The heat that we feel from sunlight, a fire, a radiator or a warm sidewalk is infrared. Although our eyes cannot see it, the nerves in our skin can feel it as heat.

Thermal Imaging - Before & After 15 minutes of Talking on Cell Phone

Temperature analysis with infrared photographs can be used for medical reasons. Highly active areas or areas of infection can be detected easily.

Some animals can "see" in the infrared. Snakes in the pit viper family (e.g. rattlesnakes) have sensory "pits," which are used to detect infrared light. This allows the snake to find warm-blooded animals (even in dark burrows), by detecting the infrared heat that they radiate.

Old Faithful Geyser

• Old Faithful is the most frequently erupting large geyser in Yellowstone National Park. A geyser is a hot spring which erupts periodically.

Geysers in Yellowstone National Park

Bubbling Mudpots

Mudpots are hot springs which do not have much water.

ELK

Forest

Visible Light

Ultraviolet Waves• Waves carry enough energy to cause

chemical reactions–Causes sunburns, possibly skin cancer

Ultraviolet Waves

• UVA – skin aging, eye damage, can suppress the immune system. (does not cause burn)

• UVB – causes burns, snow blindness, known as carcinogen

• UVC – absorbed by ozone layer, most dangerous

Ultraviolet Radiation–UV Wand – dries

adhesives–UV Nail Polish

Dryer

Ultraviolet Radiation

• Tanning Beds – UVA & some UVB rays

X-Rays• Can pass through

skin and muscles, but not bone

X-Rays

–Air port scanners

Gamma Rays• Produced when the nucleus of an

atom breaks apart or changes– PET scans– Nuclear reactions– Destroys diseased cells

Which three types of EM waves are emitted from the sun?1. Ultraviolet waves2. Visible light waves3. Infrared waves

QOD#212-14-13