Boyle's Law Apparatus

Apparatus for the recording of pressure versus volumes and for investigating Boyle's Law. The vertical tube is part-filled with coloured liquid and sealed. The trapped air is then compressed progressively, with pressure (p) and volume (v) readings taken at each stage. Before each pair of readings is taken, the liquid should be allowed to settle so that the heat caused by the compression is dissipated. Please note: oil is no longer included as coloured water can be used instead.

Q = I know that oil is no longer included with this apparatus, but if I do want to use oil, what type would you recommend?
A = Any light (i.e. thin or less viscous) engine oil will be fine for the Boyle’s law apparatus.  2-stroke engine oil is also suitable and has some colourant in it, which will make it more visible.

Q =  I have concerns that if I use water instead of oil in the Boyle's law apparatus there will be a risk of rusting - is this the case?

A = We have had no reports of rusting or corrosion caused by using coloured water in the Boyle's law apparatus - and they have been supplied without oil for a few years now. In fact the manufacturer recommends that coloured water can be used instead of oil. When questioned why the recommendation has changed, they say that oil has traditionally been used due to the risk of some of the internal parts rusting. However, they now use non-rusting parts in the manufacture so it is no longer necessary to use oil. In fact they claim it works better with water!

If you would rather use oil it will still be perfectly alright to do so - any light (i.e. thin or less viscous) engine oil will be fine to use.  2-stroke engine oil is also suitable and has some colourant in it, which will make it more visible.