Nucleation of Water
Farrin A. Reid
March 24th, 2007
Purpose
The purpose of this experiment was to examine the nucleation and possibly get media of super cooled water and superheated water.
Theory
The theory behind this experiment is that when water is relatively pure it will hold an effect when super cooled or superheated in which when a foreign crystal or possibly anything will create a nucleation site where it will start freezing from those points, or instantly boiling. This affect creates an enthalpy of fusion. To put it succinctly, if say you had a cup of water supercooled to -4 C, to freeze the temperature must rise to 0 C. If you could place a temperature probe in it without freezing, and then introduce a nucleation site ( a ice crystal will do quite nicely) it will start to freeze from that point. You will see that the temperature will increase to 0 degrees then proceed to cool down past that once again
Apparatus/Procedure
The equipment used was:
Microwave oven
Pyrex measuring cups
Pyrex fruit cups
Pyrex pie glassware
Fridge
Indoor outdoor thermometer
Thermometer probe
6 gallon water jug
Water
Dawn dish soap
Isopropyl Alcohol
10W-30 motor oil
All glass containers were rinsed thoroughly fist with tap water and dawn soap then rinsed out 3 times with the double distilled deionized water I got from the chemistry department. The water was in my 6 gallon jug that was properly cleaned out. I would place the small bowls of my water in an environment that would be exposed to the cold, but not directly and the only agitation would occur from entering the place.
I tested many different methods of trying to supercool the water. First I tried just leaving the water in the glass as it was, just open to the air. I also tried placing saran wrap over the fruit cup. Sometimes I would turn over the saran wrap just before the water would get to a freezing temperature. I also tried putting water into the fruit cup then adding a layer of isopropyl alcohol on top. I also put 10-W-30 oil in a cup then added water droplets to be suspended and separated from the glass. I also placed isopropyl alcohol in a larger fruit cup then lowered a smaller fruit cup with my water sample into it.I also placed some inside of a freezer of a refrigerator.
I would measure the temperature with a wireless temperature sensor in the room (I assumed that if there would be supercooled water when I would come back it would be the temperature of the room… I would let the water set out in the cold for 2 hours sometimes)
The supercooling precess in action!