How does that work then...?

[WillyNelson]

I'm having a bit of a slow moment and I can't for the life of me work out how the min side on this max/min thermometer works. When it gets colder, how does the liquid in the left hand min side move up the scale?

 

[WillyNelson]

But surely if the liquid is in the bottom of the U, a sit expands both sides will go up?

 

[WillyNelson]

Thanks, all makes sense now. The alcohol at the top of the min scale reacts to the temp while the liquid in the U merely indicates it.