Great set of four color-coded word searches! Includes the following:
~States of Matter
~Element or Compound?
~Simple Machines #1
~Simple Machines #2
All have the colors left blank except for the Element or Compound, but that only requires green and yellow--the rest you can have the kids choose the colors and fill them in based on what you have available.
Don't forget you can also use colored pencils, crayons and markers to differentiate the colors, you don't have to use highlighters!!