wednesday, september 25, 2015 take out the following: pen or pencil planner (p. 33) energy...
TRANSCRIPT
Wednesday, September 25, 2015
Take out the following:Pen or pencilPlanner (p. 33)Energy Workbook (p. 28)
Electromagnetic Energy: page 28
Electromagnetic Waves
Travel as Transverse waves
Do not need a medium to move through.
Medium: a material through which waves travel.
Visible Light
The only part of the spectrum that we can see.
Every light source is made up of a different combination of colors.
Spectroscopes
An instrument used to observe the spectra of light sources.
Spectroscopes
Fluorescent
Incandescent
LED
String Lights
Why does light look white?
When you mix all colors of light together, the light appears white.
Why do we see different colors?
Objects absorb some colors and reflect others.
Light Source
Colors Absorbed into object
Color reflected
from object to eye
Why do we see different colors?
Objects absorb some colors and reflect others.
Apple in the dark…
A!!!
You will NOT see the apple…EVER…
Radio Waves
Have long wavelengths & low frequencies.
Microwaves use radio waves.
Infrared Radiation
Wavelength is slightly longer than visible light. Example: we are warm, because we are
absorbing infrared radiation from the sun.
Ultraviolet Light
Has a higher frequency. Can be healthy: Vitamin D, Hospitals use to
kill bacteria & viruses to sterilize. Overexposure can be harmful: kills healthy
cells, leading to skin cancer. We are protected by the ozone layer.
X Rays & Gamma Rays
X Rays: Very short wavelength. Have higher energy and greater penetrating
power.Gamma Rays have highest frequency.
Are emitted from nuclei of radioactive atoms.
Example: Cancer Treatment