MIT's Great Dome is 147 feet above ground level, and the "Halfway to Hell" Smoot marker on the Harvard Bridge is not at the true center of the span. These are two of the facts revealed during the making of a new MIT Video Series on Measurement, which is shooting on location around campus and at other sites.
The series of eight videos is being produced by J. Tracy Pierce of the Center for Advanced Engineering Studies and written by R. John Hansman, professor of aeronautics and astronautics, who also does the on-camera demonstrations of various types of measurement.
The tapes will be marketed to industry as well as advanced high school and college students. Each tape addresses a specific topic, so viewers can go directly to the one that addresses their measurement question. Among the titles are "Distance, Velocity and Acceleration," "Mass, Force, Strain, Torque and Pressure Measurement" and "Infrared Temperature Measurement."
Each video, which is about 40 minutes long, features classroom explanation followed by real-life demonstrations of techniques.
"We've done all kinds of hands-on, practical things. We're bringing this material out of the lab and into the field," Ms. Pierce explained.
To this end, Ms. Pierce, Professor Hansman and the crew have ventured to various parts of the campus, including the Wright Brothers wind tunnel, Lincoln Laboratory's test flight facility and the rifle range as well as the dome and the bridge. They have also taped Professor Hansman explaining concepts at the top of Mt. Washington and inside a hovering helicopter. The equipment used in demonstrations was loaned by Omega Engineering of Stamford, CT.
The crew is being assisted by Cullinan Engineering, which does MIT's surveying work. In the process of employing triangulation to measure the height of the dome (an operation that required the participants to use mountain-climbing rope and harnesses as they scaled the building), Professor Hansman found a brass surveying benchmark dating from 1927 buried in the ground. "We didn't know it existed until the surveyor told us about it," he said.
Last week, the film crew traveled to Washington, DC, to the National Institute of Standards and Technology (NIST), where two master kilograms are kept inside an argon-filled vault. The crew filmed a master calibration performed by NIST staffers, as well as the world's largest force calibration testing facility. Among other measurement items of interest housed at a NIST museum is a master cubit, an ancient Egyptian measure used in the construction of the pyramids (it was based on the length of the forearm of Pharaoh Amenhetep I, who lived more than 3,500 years ago).
Also on the Washington agenda was a visit with Oliver Smoot '62, the man who went down in history in 1958 when his Lambda Chi Alpha fraternity brothers used him as a unit of measurement for the Harvard Bridge (something he still gets teased about occasionally when at NIST). While calibrating the measurement, Professor Hansman found that the legendary Smoot markers are not quite accurate-the center mark on the bridge, which purportedly measures 364.4 Smoots plus one ear, is slightly closer to Boston than to Cambridge.
Three of the eight tapes are already available, and Ms. Pierce expects to finish taping for the completed project by July.
A version of this article appeared in MIT Tech Talk on June 7, 1995.
