infrared physics waves f5

8/13/2019 Infrared Physics Waves f5

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Afifah bt Mohamed Sufian

Adibah Nabilah bt Azman


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Infrared lightlies between the visible and microwave

portions of the electromagnetic spectrum. Infrared light has a range of wavelengths, just like

visible light has wavelengths that range from red lightto violet.

"Near infrared" light is closest in wavelength to visiblelight and "far infrared" is closer to the microwaveregion of the electromagnetic spectrum.

The longer, far infrared wavelengths are about the size

of a pin head and the shorter, near infrared ones arethe size of cells, or are microscopic.


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Far infrared waves are thermal. In other words, we

experience this type of infrared radiation every day inthe form of heat!

The heat that we feel from sunlight, a fire, a radiator ora warm sidewalk is infrared.

The temperature-sensitive nerve endings in our skincan detect the difference between inside bodytemperature and outside skin temperature


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Shorter, near infrared waves are not hot at all - in factyou cannot even feel them.

These shorter wavelengths are the ones used by your

TV's remote control.


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The image at the right

shows a cat in theinfrared.

The orange areas are thewarmest and the white-

blue areas are the coldest. This image gives us a

different view of a familiaranimal as well as

information that we couldnot get from a visible lightpicture.


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Humans may not be able to see infrared light, but did youknow that snakes in the pit viper family, like rattlesnakes,have sensory "pits", which are used to image infrared light.

This allows the snake to detect warm blooded animals,

even in dark burrows! Snakes with 2 sensory pits are eventhought to have some depth perception in the infrared!

Many things besides people and animals emit infrared light- the Earth, the Sun, and far away things like stars and

galaxies do also! For a view from Earth orbit, whether weare looking out into space or down at Earth, we can useinstruments on board satellites.


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Satellites like GOES 6

and Landsat 7 look atthe Earth. Specialsensors, like thoseaboard the Landsat 7

satellite, record dataabout the amount ofinfrared lightreflected or emitted

from the Earth'ssurface.


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This is an infrared imageof the Earth taken by theGOES 6 satellite in 1986.

A scientist usedtemperatures to determinewhich parts of the image

were from clouds andwhich were land and sea.

Based on thesetemperature differences,

he colored each separatelyusing 256 colors, givingthe image a realisticappearance.


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This image of a building

with a tree and grassshows how Chlorophyll inplants reflect near infraredwaves along with visible

light waves. Even thoughwe can't see the infraredwaves, they are alwaysthere. The visible light

waves drawn on thispicture are green, and theinfrared ones are pale red.


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This image was taken withspecial film that can detectinvisible infrared waves.

False-color infrared images ofthe Earth frequently use a colorscheme like the one shownhere, where infrared light ismapped to the visible color of

red. This means that everything in

this image that appears red isreflecting infrared light.

This makes vegetation like

grass and trees appear to bered. The visible light wavesdrawn on this picture aregreen, and the infrared onesare darker red.


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Thank you

infrared physics waves f5

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