Waves and Light

Wavelength vs FrequencyC=L (speed = wavelength x frequency)• Speed of light is always

299792458 m/s or 300000000m/s• Predict Highest to lowest frequency

between wavelengths of 100m, .01m, .000001m

Freq Rank from Highest Lowest

Prediction 100m?-> .01m?-> .000001m?

Test Result(Do the calc)

.000001m (3x1015 Hz)

.01m(3x1011 Hz)

100m (3x107 Hz)

Conclusion As wavelength increases frequency….

Electromagnetic Radiation (EMR)

• Travels:– As waves– through empty space and substances

EMR Spectrum• How EMR is organized

– WAVELENGTH• Longest to shortest across the spectrum

– X-ray, Yellow visible light, purple vis. Light, Radio waves, UV, Gamma Ray, Microwaves, Infrared

Telescopes

• All collect and focus EMR

Visible Light Telescopes

• 2 types– Refracting telescope

• Convex lenses focus light

• Galileo– Oldest, simplest

– Reflecting telescope• Curved mirror reflects

image • Like Mr. Vargas’s

– Originally designed by Sir Isaac Newton

Gallileio vs. Newton

• Sketches include– Images and eyeballs– Outer case– Mirrors and lenses– Arrows indicating

the light’s path

Radio Telescopes• Curved surface _____ radio waves to

focus them at a pointOther types•Infra red – used to recently find dense clouds in the milky way, UV and X ray

Observatories and Light pollution• Why are observatories high on mountain

tops?• Observatories: buildings with one or more

telescopes– On top of mountains to reduce:

• Light pollution• Avoid some atmosphere

Where would be the best possible place to have a telescope?

• Satellite telescopes are much better because:– No atmosphere, no light pollution– Satellite images are sleven times clearer than

anything from Earth

Spectrographs• Most large telescopes have one hooked up to it.• Breaks light from object into spectrum• Spectrum tells us:

– Chemical composition– Temperature

Spectrograph

Temperature

ChemicalComposition

Spectrographs (cont.)

• Two types:– Absorption lines: black lines on spectrum– Emission lines: lines of color on spectrum

• Lines = Chemical Fingerprint

•These two spectrums are from the same chemical under different conditions.

Hot = EmissionCold = Absorption

To remember…

I know it-----

Need to revisit it-----