Internal energy and heat question.

[lionely]

how would you determine an error at the 100C mark in a given mercury thermometer?Your answer should consist of a labelled sketch of the apparatus you would use and brief notes on procedure. Why is it important, at the same time, to note the atmospheric pressure? If the thermometer registers 103 at 100C and has no zero error what will it register at 50C.

To determine the error could you put it in pure steam and see if the mercury goes past 100? That means the graduations would have been wrong. I'm not sure.

Please help me, give me a hint please!

 

[technician]

You are on the right track. Steam at normal atmospheric pressure is 100 Celsius

 

[lionely]

Oh! That means he's finding the upper fixed point at a low pressure?