FREEZING AND MELTING OF WATER

Raymond, Isaac, Sebastien, David, Andrew, Josh

Purpose of the Experiment

In order for a liquid substance to alter its form from liquid to solid, the substance must hit the freezing threshold of 32o F. Conversely, to reverse this alteration in the matter’s state the temperature must rise above this same freezing point. The factor shared by–and most pertinent to–this alteration is the release of energy that drives this process. To demonstrate the inherent importance of energy, we will evaluate the cooling and warming behavior of water. To do this, in this experiment we will measure the temperature during the freezing and melting of water and subsequently graph the data provided. This will determine its energy-releasing capabilities and its importance in the debate for sustainability.

Background Information

Freezing and melting temperatures are characteristic physical properties. Through this experiment, these elements for water will be determined and analyzed. This experiment will measure the time needed to freeze, and to melt water in particular.

Hypothesis

We assert that once the temperature reaches the freezing point (32o F) in less than five minutes, the water will solidify continually as it drops below this point. Inversely, once the water is heated, this increase above the freezing point will then convert the water back from a solid state to a liquid state within a minute due to the glass’s excellent heat transfer potential.

Materials Needed

• Measuring Apparatus:
  • Computer with LabView installed
  • NXT Console Interface
  • Vernier Temperature probe
  • Temperature Measurement Program

• Ring Stand
• Clamp
• Two 400mL sized beaker
• 10mL graduated cylinder
• water
• ice cubes
• salt
• spoon / stirring instrument

Experiment Procedure

Freezing Phase

1. Fill a 400 mL beaker 1/3 full with ice, then add 100 mL of water as a water bath.
2. Put 5 mL of water into a graduated cylinder and place it in the water bath.
3. Connect the probe to the computer interface. Prepare the computer for data collection by opening the Temperature measurement programme.
4. When the computer is ready for measurement, click to begin data collection and then lower the graduated cylinder with probe into the ice-water bath.
5. Soon after lowering the test tube, add some salt to the beaker and stir with a stirring rod. Continue to stir the ice-water bath for ten minutes.When ten minutes have gone by, stop moving the probe and allow it to freeze into the ice. Add more ice cubes to the beaker as the original ice cubes get smaller. Run the measurement for twenty minutes.

Melting Phase

6. Dispose the cold water and the ice and fill a beaker with hot water.

7. Place the graduated cylinder just slightly above the the hot water and begin measurement for ten minutes, after ten minutes, let the graduated cylinder be submerged but make sure that the hot water does not enter the graduated cylinder.

 

Data Entry

https://docs.google.com/document/d/1Zx4LdUNsZu3nDBKXp0wDHKE-A-yumV6xaWAk_syGo1Q/edit?usp=sharing

 

Analysis

 

The results conform to our theory. Decrease in temperature leads to increase of solidified state, while increase in temperature leads to dissolution of solid state.

 

It did, however, take longer than we predicted to freeze. We anticipated a 90 second freezing cycle but took 481 seconds due to unstable testing conditions. Heat transfer and its subsequent dissolution still in effect for each stage of the experiment, though.