ELECTROMAGNETIC WAVES &THE ELECTROMAGNETIC SPECTRUM

SPECTRUM• The pattern light produces when passed

through a prism or spectrograph• Prism – 3 dimensional object that refracts

light.• Spectrograph – device that allows us to see

the spectrum

ROY G. BIVredorangeyellowgreenblueindigoviolet

Visible LightRemembering the Order

ELECTROMAGNETIC WAVES• Transverse • Electric and Magnetic• Can travel through empty

space (able

• Wavelength the length of one wave

• Frequency how often something happens• With waves, it's "how

many waves per second“• Brainpop; WAVES

• Electromagnetic waves travel VERY FAST – around 300,000 kilometres per second (the

speed of light).All electromagnetic waves travel at the same speed. (300,000,000 meters/second) in a vacuum.

At this speed they can go around the world 8 times in one second.

ELECTROMAGNETIC SPECTRUM• They all have

different wavelengths and different frequencies.

• Long wavelength-lowest frequency

• Short wavelength highest frequency

• The higher the frequency the higher the energy.

• Brainpop: Electromagnetic Spectrum

Nuclear Power

HealthcareSunlightSanitize

ROY G BIV

CookCommunicat

e

Shorter Wavelength

More energyHigher

frequency

Longer WavelengthLess energy

Lower frequency

HeatRemote control

SPECTRAL ANALYSIS LAB

Stars – Spectral Analysis

Purpose: To determine the composition of stars using a spectral analyzer.

Background:1. A spectrum photograph can be sorted across a plate to reveal spectral lines.2. Lines represent the chemical composition of the star so each star has its own fingerprint.

Procedure:1. Examine each star (A, B, C, D) for chemical composition2. If lines match, the element is present.3. Check the box if the element is present.

ON BACK OF LAB SHEET:TALLY # OF LINES FOR EACH COLOR

Star Indigo Blue Green Yellow RedABCD

Answer this question on the back:

Why do astronomers need to know what elements are in

stars?Turn in lab sheet

STUDENT HANDOUTS