[sdiy] Software synth and scope for school

[David Brown]

A local grade school would like to do some classes and labs on sound 
and audio.  What they would like is some software which would allow 
generation of audio signals in various waveforms, the ability to 
adjust the waveforms such as amplitude, frequency, and waveform type, 
and to hear and see the resulting waveforms.

Seems to me that a package that allows software synthesis along with 
a software scope would do the trick.

Anyone know of such a thing or could recommend pieces?  It's been a 
while since I have looked at any of the free software synthesizers so 
I don't know what is available.  Remember this is a grade school so 
it has to be simple and free (or very inexpensive).

I'd appreciate any and all leads.

Dave