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
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…
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