Does the Size of a Manometer Tube Affect Pressure Measurement Accuracy?

  • Level: High School 
  • Thread starter Thread starter fishingspree2
  • Start date Start date
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
Sign up Log in
1 reply · 2K views
fishingspree2
Messages
138
Reaction score
0
Hello

The teacher said that one way to measure the pressure of a gas enclosed in a room is to attach a manometer to it, like in that picture:
[PLAIN]http://img842.imageshack.us/img842/3994/manometer.jpg

By doing so, aren't we changing the volume the gas has access to, and thus changing the pressure of the gas?

Thank you very much
 
Last edited by a moderator:
Physics news on Phys.org

Discussion

Yes, there will be volume increase so decrease in pressure in the system. But there is no difference how big the diameter of the tube will be so more precise measurement you will have if the diameter of the tube is small so the increase of volume is small in respect of the volume of the system so you don't take it into account.