How is heat transferred to a thermometer? Quick question. I can't seem to find a satisfactory answer online. How does a thermometer measure the average kinetic energy of atmospheric air? I assume that the energy is transferred by molecular collisions, and this somehow raises the temperature of the alcohol by doing work on the thermometer. Is this correct? Somehow a thermometer acts as a speedometer right?
 A: Taking out your last analogy about the speedometer (which I don't find useful but it might work for you), I would add that in a sealed thermometer, thermal equilibrium between the external media and the alcohol is mostly reached by exchange of electromagnetic radiation (photons). But heating or cooling or the glass molecules by atmospheric gas and then from the glass to the alcohol also plays a role, albeit minimal in most circumstances.
A: So far, you have three answers to the "how is the heat transferred" part of your question, but nobody's answered the other part:

How does a thermometer measure the [temperature] of atmospheric air?

The answer is that both the glass and the liquid inside the glass expand when they are warmed and contract when they are chilled, but they expand/contract differently.  When the thermometer is warmed, the  liquid expands by more than the volume of the hollow space in which it is confined, and so some of it must move from the bulb into the capillary tube.
A: It should be conduction and then convection/advection, not radiation. Radiation is usually the slowest heat transfer.
Conduction would be the molecules being measured smacking the glass causing them to vibrate more. The glass molecules, now vibrating faster, would smack the liquid inside and a bit of convection/advection takes place within the liquid.
