Lab Worksheet

Principles of saturation for pressure measurement
You must write up this work in the form of a report and submit to lab assistant in two weeks to receive feedback. Name:
Std. No:

Equipment (per group)
Number
1
2
3
4
5

Item
Armfield TH3-A/B/G Saturation Pressure Apparatus
Armfield TH3-A/B/G Saturation Pressure Apparatus Electric Console
500 ml Beaker
PC with TH3 software
Stopwatch

Learning Outcomes
1
2
3
4

Learning Outcome
To understand principles of saturation pressure measurement
To determine the principle of steam and P-V-T relationship
To work with data tables
To write a report based on theoretical knowledge and experimental results

Objective(s)
The objectives of these experiments are:



To measure the saturation pressure of water using a pressurised vessel.
To examine the effect of unsteady conditions on measurement accuracy.

1

Lab Worksheet
Theory
Saturation temperature is known as the boiling point of water. It is the temperature for a corresponding saturation pressure at which a liquid boils into its vapor phase. The liquid can be said to be saturated with thermal energy. For water, it is common knowledge that it boils at 100 °C and froze at 0 °C. However, this is only true if the water is at a pressure of 1 atm (100kN/m2). Decrease in the water pressure causes the boiling point to declines and vice versa. The relationship between pressure and temperature of boiling water can be plotted on a so-called transition or phase diagram shown in Figure 1. On diagram, the critical point is where particles of water in the gas phase moves very, very rapidly. At any temperature higher than that, the gas phase cannot be made to liquefy, no matter how much pressure is applied to the gas. On the other hand, the critical pressure is the pressure that must be applied to the gas at the critical