Blackbody+Radiation

Blackbody Radiation A blackbody is an object that's radiation emits into space which originates completely from its own temperature. The matter and radiation that bounce around in a blackbody are caused by the jiggling motions of its atoms. Blackbody radiation are the waves the blackbody emits. Blackbody spectra do not depend on an object's chemical composition, its size, or its age. Every time you see a star and realize what colour it is, you have taken the temperature of that star because the colour depends on the stars temperature. This is important in astronomy to study how and why stars and other planets are like that. Blackbodies aren't just black, they can be blue or red or yellow. They're just called blackbodies because anything black absorbs all the wavelengths(colours) of light that fall onto it. A blackbody pumps radiation into space different than other things. A blackbody must have heat and must be dense enough.

Play around with this applet to understand more: [] On this applet you can play around with the size of star(although it doesn't change the temperature) to see how its radius and luminosity affect it. Move it right to make it bigger and move it left to make it smaller. Then you can change the temperature of the star. It's shown in Kelvin and the more right it is, the hotter it is. It is like that because nothing can be colder than 0 Kelvin, so anything higher is hotter. If you remember the order of the colours from the largest wavelength(lower frequency) to the smaller wavelength(higher frequency) it's Red Orange Yellow Green Blue and Violet. Think about a fire on earth, the outer flames are red and as you get hotter, the flame turns yellow. Some stoves on earth can only reach infrared or red, and some can even reach blue. When something is white-hot that means that it has all the range of colours and is the hottest flame that we can see. See what you can make the star do. On the y-axis is the intensity of the radiation from the blackbody. The higher it is, the more intense the wave.

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