Here is a set of superb Science Animations.

Play them online, or download them to your laptop/computer. You can even download the whole website.  Instructions provided!

Website:

http://phet.colorado.edu/en/simulations/category/new

Here are some very useful animations for Light and Sound

The sound animation set contains a virtual oscilloscope !

Science of Light Animations

Science of Sound Animations

You can also download a free virtual signal generator from

http://heliso.tripod.com/download/generator/dsg.htm

Also, you can download a free 21 day trial of a combined virtual oscilloscope and signal generator from  http://www.virtins.com/