# How does density of paraffin wax change with temperature in a solar heater? Is there any equation?

I need to know what is the relation between density of paraffin wax and temperature in a solar water heater. I need to know the equation of density in terms of temperature.

• I doubt there will be any theoretically-derived equation for this. I think you will need to search to see if you can find some published experimental data for the thermal expansion of that substance, or conduct an experiment yourself. – Time4Tea Oct 13 '18 at 15:21

Anton Paar Wiki reports these values for the density of paraffin wax:

Specifying that their measurements cannot be made under 60°C because of the solidification of the wax.

While in this paper they used a formula to describe the behavior of its density in terms of temperature (in Kelvin): $$\rho(T) = \frac{750}{0.001(T-319.15)+1}$$

Plotting them side by side: