Density, temperature & water structure

You will notice that the apparatus does not allow us to drop the temperature below 0.00°C, the temperature at which water freezes.

Liquid water can exist at temperatures below 0°C. This is known as supercooled water.  Supercooled liquid water is not stable, however.  A loud noise or a thump can induce freezing.  When water goes from a liquid to a solid, its density changes rapidly and dramatically -- it decreases from ~ 0.9999 g/ml to ~ 0.93 g/ml.

 

EXPERIMENT

 

Use the apparatus to determine the temperature at which liquid water has the highest density – include an image of your data graph!

 
Experiment 1 write-up: answer these questions individually
  • Q1: Why can changes in volume be used to estimate changes in density?
  • Q2: Where might errors creep into your observations?
  • Q3: Why don't all liquids display a temperature versus density relationship similar to that of water? 
  • Q4: If a single molecule does not have a temperature, what does temperature measure?
  • Q5: Why is ice less dense than water?
  • Q6: What would happen to our apparatus if the water in it froze?
Use Wikipedia | revised 17 December 2004