Radar was developed secretly for military use by several nations, before and during World War II.The term was coined in 1940 by the United States Navy as an acronym for RAdio Detection And Ranging. It entered English and other languages as a common noun, losing all capitalization.
Radar uses radio waves to determine the range, angle, or velocity of objects.
EM waves can be of many different wavelengths.
Longer wavelengths we perceive as orange and red
Shorter wavelengths are towards the blue end of the spectrum
Fields are at right-angles to each other
They travel through vacuum (empty space) at the speed of light
c = speed of light
c = 3 x 108 m/s = 186,282 miles/second
So all parts of the EM spectrum – radio, light, Wi-Fi, X-rays,
are all made of exactly the same thing! The only thing different among them? wavelength and frequency!
Our eyes can only see a tiny amount of the EM spectrum.
There are longer and shorter waves as well.
Is used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain.
A radar system consists of:
transmitter producing electromagnetic radio waves
a receiving antenna (often the same antenna is used for transmitting and receiving)
a receiver and processor to determine properties of the object(s)
Radio waves from the transmitter reflect off the object and return to the receiver
This gives info about the object’s location and speed.
air and terrestrial traffic control
air-defence systems / antimissile systems
marine radars to locate landmarks and other ships
aircraft anticollision systems
outer space surveillance and rendezvous systems
meteorological (weather) precipitation monitoring
flight control systems
guided missile target locating systems
ground-penetrating radar for geological observation
6.MS-PS4-1. Use diagrams of a simple wave to explain that (a) a wave has a repeating pattern with a specific amplitude, frequency, and wavelength, and (b) the amplitude of a wave is related to the energy of the wave.
HS-PS4-1. Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling within various media. Recognize that electromagnetic waves can travel through empty space (without a medium) as compared to mechanical waves that require a medium.
HS-PS4-5. Communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy. Clarification Statements:
• Emphasis is on qualitative information and descriptions.
• Examples of technological devices could include solar cells capturing light and
converting it to electricity, medical imaging, and communications technology.
6. Electromagnetic Radiation Central Concept: Oscillating electric or magnetic fields can generate electromagnetic waves over a wide spectrum. 6.1 Recognize that electromagnetic waves are transverse waves and travel at the speed of light through a vacuum. 6.2 Describe the electromagnetic spectrum in terms of frequency and wavelength, and identify the locations of radio waves, microwaves, infrared radiation, visible light (red, orange, yellow, green, blue, indigo, and violet), ultraviolet rays, x-rays, and gamma rays on the spectrum.