Transcript Uses of EM Waves

Click here for an
interactive EM
spectrum
[http://imagers.gsfc.nasa.gov/ems/ircat.gif]
Types of EM Waves
• Radio Waves
• AM and FM Radio
• Radar – Radio Detecting and
Ranging
• MRI – Magnetic Resonance
Imaging
Click here for a Radar animation
[http://upload.wikimedia.org/wikipedia/commons/thumb/7/72/Radio_transmition_diagram_en.png/800pxRadio_transmition_diagram_en.png]
Types of EM Waves
• Microwaves
• Microwave Ovens heat food by
vibrating water molecules.
• Satellite Communications and
GPS systems
• Cell Phones
Click here for cell phone SAR ratings
Types of EM Waves
• Infrared
Waves
• These carry
thermal
energy (heat)
• Thermal
Photographs
[http://www.thermal-imaging-survey.co.uk/archive/images/buildi1.jpg]
Thermal Imaging shows infrared
waves…
Night Vision amplifies available
light waves…
[http://www.extremecctv.com/images/producttype/ThermalIR-vs-ActiveIR.pdf]
Types of EM Waves
• Visible Light
• The only EM
wave humans
can see, it
produces the
colors around
us.
Types of EM Waves
• Ultraviolet Waves
• Can cause sunburn and skin
cancer, but also needed for
skin to produce Vitamin D.
• Can kill bacteria.
Types of EM Waves
• X-Rays
• Can travel
through soft
tissue, but are
stopped by bones
to make medical
“X-Rays”
• Airports to inspect
luggage.
[http://www.physiciansfirstinc.com/handsx.gif]
Types of EM Waves
• Gamma Rays
• Ultra-High frequency waves that
can break molecular bonds.
• Radiation therapy can kill
diseased cells, but if not
controlled can also kill healthy
cells.