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