Dueling Beams of Light

The computer-based color explorations allow millions of colors to be viewed efficiently, but do you really believe it? Make and mix your own beams of colored light to see what happens.

Materials

Two overhead projectors, or two slide projectors, or one of each

If using overhead projectors, two sheets of thick paper or cardboard with cut out slightly smaller than filters If using slide projectors, two slide holders for filters


Filters

Pack of color filters (at least 6 colors - red, green, blue, yellow, magenta, and cyan) from a distributor of science education materials. You may also order filters from lighting companies that sell colored gels for theater productions – see source of equipment.

Courtesy of Bob Van Milligan who attended the
MVH workshop in Portland, Maine during June, 2006.

Color	Rosco Filter
Red	Deep Salmon #42
Green	Standard Green #2004
Blue	Light Sky Blue #67
Yellow	CalColor90 Cyan #4390
Magenta	Light Straw #11
Cyan	Calcolor90 Magenta #4760

Make your own filters using petri dishes, food color, and food dye

What To Do

Darken room

Turn on both projectors, put filters in place to color each beam, and merge beams.

Challenge 1: Find two color filters in which the merged beams of filtered light produce yellow.

Challenge 2: Stack these two colors over one beam of light (turn off second projector) and see what color is produced.

Challenge 3: Find two color filters in which the merged beams of filtered light produce your favorite color.

Challenge 4: Find two color filters that produce your favorite color by stacking the filters over one light beam.

Back to Making Color with Light Investigations

Movie of mixing red, green, and blue light

Movie of mixing red and green light

Movie of mixing red and blue light

Movie of mixing yellow and blue light

Movie of stacking fillers over one beam of light

Movies created by Marion Tomusiak,
Museum of Science, Boston