6F10.10 - Color Box and Color Mixing

Code Number:
Demo Title:
Color Box and Color Mixing
Colors and Spectrum
Area of Study:
Color Box, red, blue, and green light sticks, paper towel, razor blade, and clear plastic cup. Large, medium and small LED light bars, gratings or grating glasses.

Varying amounts of red, blue, and yellow light are mixed together to make different colors with the color box.  Each color is on its own Variac so that the intensities and amount of colors added can be controlled.

Snap the light sticks to that they start to glow.  Cut the end off of each light stick with the razor blade and pour into the plastic cup.  Dip a paper towel into the cup and absorb some of the liquid.  This liquid should give off a nice white glow.

NOTE: When the three liquids are poured into the cup the resulting mixture will have a red tint.  This is due to the dye that is in the red light stick and the thickness of the dye that the light is moving through.  The light moves through very little dye when the liquid is on the paper towel, thus giving a white color.

The large and small light bars all show the same phenomenon.  The very large light bar has LED lights and is used for large classes or audiences.  Look at the lights through a grating and observe that each individual color has a unique spectrum.  This light bar also has switches on each individual bulb so you can look at only one color at a time if desired.  The medium size light bar has LED's whose colors can be changed with the control panel to show the spectrum of the individual colors.  The small light bar also has a switch so that you can have all the LED's on at the same time or turn them on one at a time if desired.  This one is small enough so that it is most useful in a smaller classroom or with a small audience.

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Disclaimer: These demonstrations are provided only for illustrative use by persons affiliated with The University of Iowa and only under the direction of a trained instructor or physicist.  The University of Iowa is not responsible for demonstrations performed by those using their own equipment or who choose to use this reference material for their own purpose.  The demonstrations included here are within the public domain and can be found in materials contained in libraries, bookstores, and through electronic sources.  Performing all or any portion of any of these demonstrations, with or without revisions not depicted here entails inherent risks.  These risks include, without limitation, bodily injury (and possibly death), including risks to health that may be temporary or permanent and that may exacerbate a pre-existing medical condition; and property loss or damage.  Anyone performing any part of these demonstrations, even with revisions, knowingly and voluntarily assumes all risks associated with them.