#5 - Reflection Light and Color for Nonscientists PHYS 1230...

Info iconThis preview shows pages 1–10. Sign up to view the full content.

View Full Document Right Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Reflection Light and Color for Nonscientists PHYS 1230 Geometrical optics - how does light change direction? Reflections (mirrors, seeing your image) Pace of Class? A) Too slow B) Too fast C) Just right Examples of Reflections RADAR SONAR Radio wave (AM) propagation Reflection from a mirror Reflection from glass Silvered sunglasses Periscopes Magic mirrors Two-way mirrors Sun pillars Demonstrations and Simulations on Reflection Rope tied to a wall - hard reflection Rope tied to a string - soft reflection Full reflection - you image in a vanity mirror, reflection from a mirror Partial reflections - image in glass window, half-silvered mirror Colored reflections - gold mirrors, aluminum mirrors, silver mirrors http://phet.colorado.edu/new/simulations/sims.php?sim=Wave_on_a_String http://micro.magnet.fsu.edu/primer/java/reflection/reflectionangles/index.html Geometrical optics - Reflections Light travels in straight lines until it reflects off something Reflections of any kind of wave occur whenever the medium of propagation changes abruptly e.g. rope tied to a wall or a string What counts is the change in the waves speed of propagation. If no speed change occurs, there is no reflection If the speed changes dramatically, most of the wave is reflected. If there is little change in speed, little reflection occurs http://www.glenbrook.k12.il.us/gbssci/phys/mmedia/waves/fix.html Reflections Hard reflections: wave goes from fast medium to a slow medium Slow reflections: wave goes from slow medium to a fast medium Applications of reflections - RA dio D etection A nd R anging Radar is based on reflected or echoed electromagnetic waves of a billion hertz (or what wavelength?) If we know the speed of the wave, we can send out a pulse towards an object, and measure how long it takes for the reflection to return to us. Then - Distance = speed x time RA dio D etection A nd R anging for Weather Forecasts Doppler radar is a type of weather radar that determines whether atmospheric motion is toward or away from the radar. It uses the Doppler effect to measure the velocity of particles suspended in the atmosphere. It employs the apparent shift in frequency of radio waves to perceive air motion and consequently predict tornadoes and precipitation sooner than previous radars, as well as measure the speed and direction of rain and ice. http://www.weather.com/maps/maptype/dopplerradarusnational/index_large_animated.html www.crh.noaa.gov/lmk/glossary.htm Radar transmits a pulse, then measures reflected echo (backscatter ) by Tony Freeman, Jet Propulsion Laboratory An imaging radar works very like a flash camera in that it provides its own light to illuminate an area on the ground and take a snapshot picture, but at radio wavelengths. A flash camera sends out a pulse of light (the flash) and records on film the light that is reflected back at it through the camera lens. Instead of a camera lens and film, a radar uses an antenna andthrough the camera lens....
View Full Document

Page1 / 49

#5 - Reflection Light and Color for Nonscientists PHYS 1230...

This preview shows document pages 1 - 10. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online