Electromagnetic Waves Objectives Know the names of each type of wave. Know the order of the waves according to the wavelength/frequency Know what each of the waves are used for Know that all EM waves can travel through matter and empty space Know that all of the EM waves travel at the speed of light

Electromagnetic Waves 2-10-14 Electromagnetic Waves Electromagnetic waves (radiant energy) – waves that can travel through empty space and through matter. All EM waves travel at the speed of light.

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

Electromagnetic Spectrum Longer wavelengths Lower frequencies Lower energy Shorter wavelengths Higher frequencies Higher energy wave Light Roman Men Invented Very Unusual X-Ray Guns

Electromagnetic Spectrum Longer wavelengths Lower frequencies Lower energy Electromagnetic Spectrum Higher frequencies Higher energy wave Light -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 Radiowaves Used for communication Radio stations Television stations

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 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

QOD#21 Which three types of EM waves are emitted from the sun? 2-14-13 QOD#21 Which three types of EM waves are emitted from the sun? Ultraviolet waves Visible light waves Infrared waves