Way back in the old Mac OS 9 days, I religiously used excellent simulation software from Yves Pelletier - those simulations were just what my physics students needed to understand vital concepts. Well, Yves is at it again, this time with many excellent QuickTime animations of key physics concepts. These simulations are a perfect addition for your Powerpoint classroom presentations.
You can find all of Yves' animations here - each one for the very reasonable price of $5.