Ohaus USA Balance Tutorials (see "Ohaus Triple Beam")
http://www.ohaus.com/products/education/tutorials.asp?source=2

From "set-up and care," show the following slides: Transporting the 
Balance; ?Balance Parts?

Show "use tutorial" up to slide (but not including) slide entitled, 
"Specific Gravity Determinations."

Students use "practice weighing" (TBB Scale Reading Exercise) to correctly 
determine the mass of three unknowns.