Estimation of the errors in determining the coefficient of thermal expansion for a plastic

Conclusions

• 1. As α for a plastic often varies with t, it is suggested that one should measure either a mean α over a wide temperature range or the value α_tn in the range from t_n–5°C to t_n +5°C.

• 2. The errors indicate that 10°C should be the narrowest temperature range used.

• 3. Acceptable standard deviations for Δl and Δt are set in relation to α on the basis thatl ₀ is measured to 0.010 mm and that α_tn has to be measured with a relative error of 10% or 20%.