I loosely followed this lesson plan with my 6th graders last year-
We mummified oranges and potatoes- the body was the orange and the head was
carved from a potato, then they are wired together.
The website has enough information to follow, or you can order a more
detailed unit plan (which I haven't seen.)
It was great fun- then we made paper mache mummy cases.
It was a definite hit-