Wednesday, September 25, 2015 Take out the following:  Pen or pencil  Planner (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