David has taught Honors Physics, AP Physics, IB Physics and general science courses. He has a Masters in Education, and a Bachelors in Physics.
What Is Infrared Radiation?
Infrared radiation is made up of electromagnetic waves of a particular wavelength just beyond what we can see on the red side of the spectrum. They were first discovered by William Herschel around 1800.
Other electromagnetic waves include radio, microwaves, visible light, ultraviolet, x-rays, and gamma rays, but electromagnetic waves that are between 700 nm and 1 mm are classed as infrared. 1 millimeter is equal to 1,000,000 nanometers!
Infrared is all around us: Most warm objects, including the human body, release radiation of this wavelength, heat-sensitive cameras work by detecting infrared radiation, and half of the energy emitted by the sun is infrared.
Uses of Infrared Technology Radiation
One of the most common uses of infrared radiation is in heat-sensitive thermal imaging cameras. These can be used to study human and animal body heat patterns, but more often, they are used as night-vision cameras. These have uses in warfare, as security cameras and in nocturnal animal research.
Most remote controls operate by sending pulses of infrared, spelling out codes that an electronic device will recognize. This includes TV remotes, DVD players, projectors, etc. Infrared is often used to send signals through fiber optic cables, particularly when using standard silica fibers. Fiber optic cables are commonly used to transmit audio to sound systems and for high-speed Internet connections.
Infrared is also widely used in astronomy. Taking pictures of the universe in infrared can lead to some amazing discoveries. Astronomers can look at an area of the sky that appears empty and dark in the visual part of the electromagnetic spectrum and find the area full of activity in the infrared. Since most objects that are at all hot produce infrared radiation, whereas plenty of objects do not produce visible light, it is a vital tool in observational astronomy.
One issue with infrared astronomy is that infrared tends to be absorbed by water vapor in the atmosphere. Positioning telescopes at high altitudes can help reduce this issue, as can putting telescopes in balloons or planes. However, since the Hubble Space Telescope was launched in 1990, we have entered a new era in infrared astronomy - space telescopes are able to conduct infrared photography with no interference from the Earth's atmosphere whatsoever. As a result, we have some stunning images that we could never have achieved on Earth.
We have detected many objects using infrared astronomy. These include cold and dark dust clouds heated by nearby stars, protostars that haven't begun to emit light, and planets that would be drowned out by their stars when viewed in visible light.
In general, infrared imagery is used a lot in meteorology. As well as looking at the energy emitted by the Earth's surface, weather patterns can be analyzed this way. Analysts can use such images over time to determine cloud heights and types and to calculate surface and land temperatures.
Effect of Infrared Radiation on Climate Change
When light from the Sun arrives at the Earth, much of it is absorbed by the Earth's surface. This energy has to go somewhere, and so much of it is re-emitted by the ground. However, even though the energy got here as visible light or ultraviolet, the ground re-emits it as infrared. This infrared becomes trapped by the water vapor and other greenhouse gases in the Earth's atmosphere, and it is this that accounts for the Earth's greenhouse effect.
Infrared radiation is made up of electromagnetic waves with a wavelength between 700 nm (nanometers) and 1 mm, just beyond what our eyes can detect on the red side of the electromagnetic spectrum. Most warm objects in our everyday experiences emit infrared, and half of the energy produced by the Sun is also infrared.
We use infrared radiation in many ways, including thermal imaging cameras, remote controls, fiber optic cables, infrared astronomy, and meteorology. The fact that water vapor and other greenhouses gases absorb infrared is part of why the greenhouse effect happens.
Vocabulary & Uses
- Infrared: electromagnetic waves that are between 700 nm and 1 mm
- Infrared Radiation: these wavelengths are just beyond the visible spectrum and usually created by heat
|Thermal Imaging Cameras|
When this lesson ends, students should be able to:
- Describe the features and classification of infrared
- Explain infrared radiation
- Identify the uses of infrared
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