Infrared facts for kids

Picture of dog in mid-infrared

Infrared (IR) radiation is a type of electromagnetic radiation (a wave with electricity) . The wave is longer than light which humans can see and shorter than microwaves. The word infrared means below red. It comes from the Latin word infra (meaning below) and the English word red. (Infrared light has a frequency below the frequency of red light.) Red light has the longest wavelength that human eyes can see. Infrared waves cannot be seen by the eye. The infrared wave is between 800 nm and 1 mm. People sense infrared as heat.

Most remote controls use infrared to send the control signals. Many missiles for anti-aircraft warfare find their target by infrared.

Telecommunications

Before Bluetooth was invented, some computers, personal digital assistants, and mobile phones were using the infrared technology to send files to other devices. Bluetooth replaced infrared in the early 2000's. Infrared is limited by the need to have both devices in a "line of sight" with each other.

Infrared lasers are used to provide the light for optical fiber communications systems. Infrared light with a wavelength around 1,330 nm (least dispersion) or 1,550 nm (best transmission) are the best choices for standard silica fibers.

Related pages

• Infrared spectroscopy

Images for kids

• 

  A pseudocolor image of two people taken in long-wavelength infrared (body-temperature thermal) radiation.

• 

  This false-color infrared space telescope image has blue, green and red corresponding to 3.4, 4.6, and 12 μm wavelengths, respectively.

• 

  Materials with higher emissivity appear closer to their true temperature than materials that reflect more of their different-temperature surroundings. In this thermal image, the more reflective ceramic cylinder, reflecting the cooler surroundings, appears to be colder than its cubic container (made of more emissive silicon carbide), while in fact, they have the same temperature.

• 

  Hyperspectral thermal infrared emission measurement, an outdoor scan in winter conditions, ambient temperature −15 °C, image produced with a Specim LWIR hyperspectral imager. Relative radiance spectra from various targets in the image are shown with arrows. The infrared spectra of the different objects such as the watch clasp have clearly distinctive characteristics. The contrast level indicates the temperature of the object.

• 

  Infrared light from the LED of a remote control as recorded by a digital camera

• 

  Reflected light photograph in various infrared spectra to illustrate the appearance as the wavelength of light changes.

• 

  Infrared hair dryer for hair salons, c. 2010s

• 

  IR satellite picture of cumulonimbus clouds over the Great Plains of the United States.

• 

  Beta Pictoris with its planet Beta Pictoris b, the light-blue dot off-center, as seen in infrared. It combines two images, the inner disc is at 3.6 μm.

• 

  Thermographic image of a snake eating a mouse

• 

  Infrared radiation was discovered in 1800 by William Herschel.

See also

In Spanish: Radiación infrarroja para niños