Here's a pdf for you today of an old fashioned book - Gilbert Light Experiments For Boys.
It's by a professor of physics, Carleton John Lynde, Ph.D.
It's from 1909, so it's called "For Boys". :)
Along with discovering light, illusions and a few other things are explained.
It's quaint, but interesting.
(see homeschoolfreebieoftheday.com for dailies.)