ch2 silent demonstration
didn't see the silent demonstrations? watch the video.
Want to see what others said? not shared until the day after the assignment is due
http://spreadsheets.google.com/a/pndhs.org/ccc?key=tmiGw4tGHrAn1Af4dAP2I0Q&authkey=CNzKveYK&hl=en#gid=0
flinn video by bob becker; where I got the basic idea.