More WavesMore Waves

Polarizing FiltersPolarizing Filters

• A polarizer contains lines spaced A polarizer contains lines spaced very closely together. Only waves very closely together. Only waves oriented in the same direction as the oriented in the same direction as the polarizer can pass through.polarizer can pass through.

Electromagnetic SpectrumElectromagnetic Spectrum• All waves in the EM spectrum travel at the All waves in the EM spectrum travel at the

speed of light, 3 x 10speed of light, 3 x 1088 m/s m/s

• In order from lowest frequency and energy to In order from lowest frequency and energy to the highest: Power, Radio, Microwave, Infrared, the highest: Power, Radio, Microwave, Infrared, Visible, Ultraviolet, X-ray, and Gamma rays.Visible, Ultraviolet, X-ray, and Gamma rays.

Particle Wave DualityParticle Wave Duality

• Isaac Newton determined that light is Isaac Newton determined that light is a particle.a particle.

• Christian Huygens found the wave Christian Huygens found the wave theory of light.theory of light.

• Both theories have strengths and Both theories have strengths and weaknesses because of the dual weaknesses because of the dual nature of light.nature of light.

Balmer, Lymen, and Paschen Balmer, Lymen, and Paschen seriesseries

• Balmer is the visible rangeBalmer is the visible range

• Lymen is ultravioletLymen is ultraviolet

• Paschen is infraredPaschen is infrared

Blackbody radiationBlackbody radiation

• A blackbody is one that absorbs all A blackbody is one that absorbs all radiation incident upon it. It reflects radiation incident upon it. It reflects nothing and appears black.nothing and appears black.

• A blackbody will release thermal radiation, A blackbody will release thermal radiation, and the wavelength of wave it releases is and the wavelength of wave it releases is related to the temperature.related to the temperature.

• Lower temperature substances stay black. Lower temperature substances stay black. Higher temperature substances can be Higher temperature substances can be red, yellow, white, and blue.red, yellow, white, and blue.

Greenhouse effectGreenhouse effect• Energy from the sun is mainly in the range Energy from the sun is mainly in the range

of ultraviolet, visible, and short-of ultraviolet, visible, and short-wavelength infrared. The atmosphere is wavelength infrared. The atmosphere is transparent to those wavelengths, so they transparent to those wavelengths, so they pass through to the earth.pass through to the earth.

• The earth absorbs the energy from these The earth absorbs the energy from these waves, and then reradiates it as long-wave waves, and then reradiates it as long-wave infrared.infrared.

• The atmosphere does not transmit long-The atmosphere does not transmit long-wave infrared, and the trapped radiation wave infrared, and the trapped radiation warms the earth.warms the earth.

Ozone holeOzone hole

• Ozone in the upper atmosphere prevents Ozone in the upper atmosphere prevents the harmful UVB rays from getting through. the harmful UVB rays from getting through.

• Use of cfc’s (chloroflurocarbons) has Use of cfc’s (chloroflurocarbons) has decreased the thickness of the ozone layer, decreased the thickness of the ozone layer, and seasonal changes occur naturally that and seasonal changes occur naturally that also decrease the ozone.also decrease the ozone.

• The decreased ozone has been linked to an The decreased ozone has been linked to an increase in skin cancers, damage to plants, increase in skin cancers, damage to plants, and a reduction of plankton populations in and a reduction of plankton populations in the ocean.the ocean.

Blue SkiesBlue Skies

• Caused by the scattering of light in Caused by the scattering of light in the atmosphere.the atmosphere.

• Short wavelength light scatters more, Short wavelength light scatters more, so it gets bounced around the so it gets bounced around the atmosphere.atmosphere.

• When the sun is rising or setting, the When the sun is rising or setting, the light goes through more atmosphere, light goes through more atmosphere, and the blue light gets scattered out.and the blue light gets scattered out.

LasersLasers

• LLight ight AAmplified by mplified by SStimulated timulated EEmission of mission of RRadiationadiation

• Monochromatic (single wavelength) Monochromatic (single wavelength) and in phase.and in phase.

HologramsHolograms• Three dimensional pictures made Three dimensional pictures made

with a laserwith a laser

• White light holograms can be seen in White light holograms can be seen in regular room lightingregular room lighting

• Transmission holograms require the Transmission holograms require the same type laser they were produced same type laser they were produced with to be visiblewith to be visible

DiffractionDiffraction•Bending of waves as they Bending of waves as they

pass around a barrier.pass around a barrier.

•Maximum diffraction comes Maximum diffraction comes with small slits and long with small slits and long wavelengths.wavelengths.

InterferenceInterference•Two or more waves interacting.Two or more waves interacting.

•Constructive interference – crest Constructive interference – crest meets crest or trough meets meets crest or trough meets trough.trough.

•Destructive Interference – crest Destructive Interference – crest meets trough.meets trough.

ResonanceResonance

• Object that vibrates at it’s natural Object that vibrates at it’s natural frequency is in resonance.frequency is in resonance.