I build a fully functional French style Guillotine for the same history class. Even had a figure dressed like French aristocrats that laid on the table with a head that was chopped off and fell in a basket when the blade fell.
My first complete scratch build project. It was about whatever scale Barbie dolls are supposed to be.
The nun kept it on her desk with the blade down so the other kids wouldn't be tempted to stick their fingers into it to see if the blade was really sharp.
(it was really sharp)

but not heavy enough to cut through bone more then a nick

.