A CD turned into a spinning top becomes even more fun when combining colors. Alternate equal squares of primary colors to make new colors as they spin. Here's the classic: Yellow and Blue make Green. Deceptively educational shares all of the details.
Good for age 5 and up.
Get the instructions here:
http://deceptivelyeducational.blogspot.com/2013/07/blending-colors-with-diy-tops.html
