The Electromagnetic Spectrum Different wavelengths of EM waves. These wavelengths of light and others make up a spectrum. NSF North Mississippi GK-8

NSF North Mississippi GK-8 On the Spectrum… Left Side Right Side Type of Wave Wavelength Frequency Energy Radio Gamma Long Short Low High Low High NSF North Mississippi GK-8

VISIBLE LIGHT Electromagnetic waves we can see. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Visible Spectrum The visible spectrum contains seven colors. Each of these colors corresponds with a particular wavelength. Longest wavelength= red light Shortest wavelength= violet (purple) light http://ldt.stanford.edu/ldt1999/Students/tita/mjrproj/color/wavereview.html NSF North Mississippi GK-8

How can I remember the seven colors of the visible spectrum? ROY G BIV RANGE REEN LUE NDIGO IOLET ED ELLOW NSF North Mississippi GK-8

NSF North Mississippi GK-8 White Light White light is not a single color; it is made up of a mixture of the seven colors of the rainbow. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Colour We can demonstrate this by splitting white light with a prism: This is how rainbows are formed: sunlight is “split up” by raindrops. NSF North Mississippi GK-8

NSF North Mississippi GK-8 Why do we see color? When our eyes see different wavelengths of light in the visible spectrum, we see colors. http://www.astronomynotes.com/light/colorswvl.gif Light Wavelengths NSF North Mississippi GK-8

How do humans see color? Seeing colour Homework What we actually see is the light an object reflects or in some cases the light an object produces. For example, a red book only reflects red light: Homework White light Only red light is reflected NSF North Mississippi GK-8

NSF North Mississippi GK-8 A red stoplight appears green because it produces red light. It’s LUMINOUS! NSF North Mississippi GK-8

The colors that don’t get reflected, are absorbed. Seeing colour The colors that don’t get reflected, are absorbed. Absorption – the disappearance of an electromagnetic wave into a medium. It’s the opposite of reflection! It absorbs all the other colors. (OYGBIV) Homework White light Only red light is reflected NSF North Mississippi GK-8

A white hat would reflect all seven colors: A pair of purple pants would reflect purple light (and red and blue, as purple is made up of red and blue): Purple light A white hat would reflect all seven colors: White light NSF North Mississippi GK-8

NSF North Mississippi GK-8 Using coloured light What about an outfit? Shirt looks red White light Shorts look blue NSF North Mississippi GK-8

NSF North Mississippi GK-8 Sun’s Rays (White Light) Green Wavelength of light Absorbs all other colors NSF North Mississippi GK-8

Black When you see black, all of the wavelengths of light are absorbed and no light is reflected back at you. Nothing is reflected. All visible light is absorbed. White light NSF North Mississippi GK-8

Moving on to the HUMAN EYE NSF North Mississippi GK-8