The Positive Value of Chalk Dust

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.”