Infraredfrequency

infrared     A type of electromagnetic radiation invisible to the human eye. The name incorporates a Latin term and means “below red.” Infrared light has wavelengths longer than those visible to humans. Other invisible wavelengths include X-rays, radio waves and microwaves. Infrared light tends to record the heat signature of an object or environment.

Infrareduses

This is an image of a person taken with an infrared camera. It indicates where the person’s skin is warmer (red and orange) and cooler (green and blue).

Infrared wavelengthrange in m

Bethany Brookshire was a longtime staff writer at Science News Explores and is the author of the book Pests: How Humans Create Animal Villains. She has a Ph.D. in physiology and pharmacology and likes to write about neuroscience, biology, climate and more. She thinks Porgs are an invasive species.

Editor’s note: This post was updated on September 11, 2018 at 9:35 AM EST to correct the conversion from nanometers and millimeters to inches.

Founded in 2003, Science News Explores is a free, award-winning online publication dedicated to providing age-appropriate science news to learners, parents and educators. The publication, as well as Science News magazine, are published by the Society for Science, a nonprofit 501(c)(3) membership organization dedicated to public engagement in scientific research and education.

radiation     (in physics) One of the three major ways that energy is transferred. (The other two are conduction and convection.) In radiation, electromagnetic waves carry energy from one place to another. Unlike conduction and convection, which need material to help transfer the energy, radiation can transfer energy across empty space.

Infrared wavelengthrange in nm

Everything emits a tiny bit of light. It’s not visible to the human eye because it is in the infrared spectrum. But the type and amount of light emitted changes with temperature. So animals or technologies that can perceive infrared can also see how hot or cold something is. Scientists can learn a lot about objects by sensing their temperature. For example, infrared cameras can help scientists understand what faraway planets are made of.

Near-infraredwavelength

Infrared light wavelengthand frequency

range     The full extent or distribution of something. For instance, a plant or animal’s range is the area over which it naturally exists. (in math or for measurements) The extent to which variation in values is possible. Also, the distance within which something can be reached or perceived.

wavelength     The distance between one peak and the next in a series of waves, or the distance between one trough and the next. Visible light — which, like all electromagnetic radiation, travels in waves — includes wavelengths between about 380 nanometers (violet) and about 740 nanometers (red). Radiation with wavelengths shorter than visible light includes gamma rays, X-rays and ultraviolet light. Longer-wavelength radiation includes infrared light, microwaves and radio waves.

planet     A celestial object that orbits a star, is big enough for gravity to have squashed it into a roundish ball and has cleared other objects out of the way in its orbital neighborhood. To accomplish the third feat, the object must be big enough to have pulled neighboring objects into the planet itself or to have slung them around the planet and off into outer space. Astronomers of the International Astronomical Union (IAU) created this three-part scientific definition of a planet in August 2006 to determine Pluto’s status. Based on that definition, IAU ruled that Pluto did not qualify. The solar system now includes eight planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

This is a category of light ranging in longer wavelengths from about 800 nanometers to one millimeter (that’s 0.00003 to 0.04 inch). Radiation, including visible light, comes in waves of different lengths. Some of those lengths — including infrared — are too long for our eyes to perceive them. Infrared light gets its name from the fact that these wavelengths are a bit longer than what we see as the color red. Though people cannot see infrared light, some snakes, mosquitoes and other animals can.