A large sheet of white posterboard or several pieces of white copy paper can be used in place of a white wall.
Test each light to make sure that it is projecting color.
The room should be as dark as possible.
Your brain perceives light differently than pigments such as paint. When you mix primary pigments together you get a darker color. When you mix primary lights together you get a lighter color. [5] X Research source
You may not have expected that a mixture of red and green lights would create a yellow color. The same receptors in your eyes that see yellow are stimulated when you shine a red and green light. [8] X Research source
Be sure to use glass or clear plastic cups.
This experiment works best in a darkened room. The contents of glow sticks are not toxic, but general precautions should be taken to prevent ingestion or excessive skin contact. [13] X Research source
