======Considering 3 Ways That Heat is Transferred======

1. Conduction\\
2. Convection\\
3. Radiation (new idea)\\

  * Conduction: hot object is in contact with a cooler object, the heat energy flows from the hot object to the cold object (bottom of pan on stove or putting your warm hand on cold metal)\\

  * Convection: movement of fluids (liquids/gases) more dense fluids sink and the less dense fluid rises (hot ari over sand rises, cool air from the ocean blows into land)\\

  * Radiation: We have been representing light as a ray traveling in a straight line, something like a basketball bouncing off a wall with angle of incidence = angle of reflection; this has been a helpful model for explaining pinhole cameras, way light is reflected from mirrors: light is like a particle (called a photon).\\

Now we are going to shift to thinking about light in a different way.  Sometimes you may have seen light represented by a wavy line.  In this model, it is helpful to think of light as being like a wave and this is represented by a wavy line (still moving in a straight direction).  

Resource for thinking about light this way:  Water waves
Familiar phenomena explained with this model:  rainbows
-->In this model, visible light is considered to be part of the electromagnetic spectrum (red, orange, yellow, green, blue, violet) with red having larger wavelength (about 700 nanometers) than violet (about 400 nanometers).  These are the colors our eyes can detect.  

The electromagnetic spectrum also includes bigger waves (infrared, microwaves, radio waves (very big, up to 100 km) as well as smaller ones (ultra violet, x-rays, gamma rays down to 10 (-6) nm.  (nano meter = 10-9 m)

See electromagnetic spectrum at: http://science-edu.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html
 
  * New property of materials: emissivity\\
- Hot sand, and other hot objects EMIT ENERGY\\
- Called “infra red radiation” which is Part of electromagnetic spectrum\\
- WE can not see infra red; we can see the visible spectrum; red/orange/yellow/ green/blue/violet\\
- Table: http://www.monarchserver.com/TableofEmissivity.pdf\\
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Video Clips to Help Explain what is going on:\\
http://cpucips.sdsu.edu/pettg/ \\
http://cpucips.sdsu.edu/pettg/c1/a5/c1a5.html#