The Doppler Radar, Rainbows, Sunglasses, and More!
By Ben Corbyn
The Doppler Radar
The Doppler Radar can be expressed through two items. A police radar gun, and a radar to track the speed of weather precipitation. The police radar gun works by sending a electromagnetic wave from the gun, to an object, which bounces back to the original gun, which has a receiver too. So this can tell the velocity of the object. When the electromagnetic waves are sent out, they are set at a precise frequency. But as it reflects off the moving object, it changes the frequencies of the wave. The weather radar works in pretty much the same way, but sends pulses of electromagnetic waves instead of one beam.
The Science Behind Polarized Sunglasses
Some people use polarized sunglasses for fishing or driving, but they don't know why. Here's why. Visual light in the form of electromagnetic waves can be very bright because they are a type of mixture of all sorts of frequencies. When the sunlight uses reflection off of a black or reflective material, the light can bounce into your eyes. This can be bad for the cones and rods in your eyes because they cannot process all that color, so it seems really bright. But when you use polarized sunglasses, the lenses absorb the crazy, haywire, white light. However after it absorbs the white light, it lets the more focused light like black, red, green, and blue light. This means that when you look at the reflective surface, you don't see as much brightness because of the absorption of the white light.
Rainbows and Sunsets
When people look at rainbows and sunsets, they see just a cool array of lights. But what's the science behind them? Let's start off with rainbows. Rainbows come from the raindrops acting like prisms. When the sunlight hits the raindrops, it is separated into it's different wavelengths, making the colorful array our brains see with our rods and cones.
Sunsets are a result of scattering of sunlight. As the sunlight enters the atmosphere it scatters in the oxygen and nitrogen, creating the blue we see at daytime. But at sunset, the light has to travel a much more distant path to reach you, hitting more molecules of oxygen and hydrogen, creating more of a red color.
The Dual Nature of Electromagnetic Waves
Electromagnetic waves oscillate in the form of transverse and longitudinal waves. They are the only wave that can move through a vacuum, such as space. This is because they are moving in the form of photons, which are particles. A normal wave such as sound could not oscillate in space because they are just a vibration. In space there is nothing to vibrate on, so it cannot happen. Electromagnetic waves, such as ultraviolet or visual light, can also oscillate through a medium, but slower than through a vacuum.
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"Physics in the Real World." N.p., n.d. Web. 26 Apr. 2015.
"Why Do We See Rainbows, Why Do They Work." N.p., n.d. Web. 26 Apr. 2015.