Determining Absolute Zero Using Charles' Law

Objective

To use Charles' Law to estimate the temperature of absolute zero.

Plan

  1. Heat the air in a small (125 mL) Erlenmeyer flask with a 1-hole stopper in a boiling water bath.
    heating apparatus
  2. Record the volume of air in the flask (V1) and the temperature of the boiling water bath (T1).
  3. Invert the flask into an ice water bath. (Water will come in through the hole in the stopper.)
    inverted flask
  4. Record the volume of air in the flask (V2) and the temperature of the ice water bath (T2).
  5. Calculate your measured value of absolute zero graphically by plotting Volume (dependent, on the y-axis) vs. Temperature (independent, on the x-axis) and extrapolate the graph until it hits the x-axis (where V = 0).

For Honors Students:

  1. Calculate your measured value of absolute zero algebraically by using your two data points (T1,V1) and (T2,V2) to write an equation in y = mx + b format. Solve the equation  for x (temperature) where y = 0 (volume = 0) to get absolute zero.
  2. Calculate your expected value of V2 (which we'll call VE) from the formula VE = (V1)(T2)/(V1).
  3. Your % error is | VE - V2 | / VE x 100
Last modified: Sunday, 3 June 2012, 1:19 AM