Gases are more prone to expansion and contraction than liquid . The biggest change in the volume in your thermometer was probably in the water or air

In the air

Explanation:

There are three states of matter:

- Solids: in solids, the particles are tightly bond together by strong intermolecular forces, so they cannot move freely - they can only vibrate around their fixed position

- Liquids: in liquids, particles are more free to move, however there are still some intermolecular forces keeping them close to each other

- Gases: in gases, particles are completely free to move, as the intermolecular forces between them are negligible

For this reason, it is generally easier to compress/expand the volume of a gas with respect to the volume of a liquid.

In this problem, we are comparing water (which is a liquid) with air (which is a gas). From what we said above, this means that the change in volume is larger in the air rather than in the water.

measure their densities same density, same sub