Here are some links to websites and on-line videos that might be interesting to middle-school students (plus or minus) who are studying or needing to review measurement.

Origins of length measurements

A clear, mature discussion of the history of length units just over 7 minutes

USA Customary Units — this is meant for elementary students, but might be helpful to some students who are unfamiliar with US Customary measurement about 20 minutes long

Khan academy video demonstrating conversion of US Customary length
about 8 minutes long