Chalk dust, which some people think of only as a minor nuisance and others think of not at all [see A measured look at schoolroom chalk dust], does have uses. A report from the bioengineering unit at the University of Strathclyde reveals one of them:
“Technical note: Static in situ calibration of force plates“, M.G. Hall, H.E. Fleming, M.J. Dolan, S.F.D. Millbank, J.P. Paul, Journal of Biomechanics, vol. 29, no. 5, May 1996, pp. 659-65. The authors describe “an in situ calibration protocol for ground-to-foot force measuring platforms” that “allows verification of the function of the force plate and allows accurate calibration for three force and moment channels”. One small but telling aspect:
“The force plates have grid positions semi-permanently marked out on their top surface which is parallel to the X-Z plane. The lines scored on the top surface are normally invisible to all but the closest of inspections, but are readily seen when chalk dust is rubbed onto the surface.”
