## Thursday, November 3, 2011

### Freezing and Melting Temperature of Water Lab

In this lab we were testing the temperatures of when we were freezing the water into ice and when the ice was melting into water. My hypothesis is that, if I test the two waters, then the freezing water will be colder  than the melting, because of the ice.

Results and Diagrams:

This is the results of the Freezing test

This is the results of the melting part of the lab

This shows how the two graphs compare to one another

This is when the test tube was frozen

This is the ice after the 5 minute waiting period

This is the ice as it began to melt

This is the ice as its almost completely melted

As we began to add the salt, the temperature rapidly began to decrease with the ice inside of the beaker. Then after a fifteen minute period, the ice in the test tube had froze, then we left the frozen ice tube out on the table and the temperature increased, but once we put it into the warm water, it melted. These are all shown in the photos above.

1. What happened to the water temperature during freezing? During melting?
The temperature rapidly decreased once we began to freeze the test tube, and the temperature rose slowly as it was set in the warm water.

2. According to your data and graph, what is the freezing temperature of water? The melting temperature? Express your answers to the nearest 0.1°C.
Well the temperature in Celsius when the water freezes is 0 degrees Celsius, and once the temperature is above the 0 degrees point I believe that the ice begins to slowly melt.

3. How does the freezing temperature of water compare to its melting temperature?
The temperature of the water when it was frozen, just stayed right below freezing and maintained about the same temperature throughout the test. The melting temperature was a lot warmer and changed the entire time of the test.

4. Tell if the kinetic energy of the water in the test tube increases, decreases, or remains the same in each of these time segments during the experiment.
a. when the temperature is changing at the beginning and end of Part I Decreased
b. when the temperature remains constant in Part I Remains the same
c. when the temperature is changing at the beginning and end of Part II Increased
d. when the temperature remains constant in Part II Remains the same

5. In those parts of Question 4 in which there was no kinetic energy change, tell if potential energy increased or decreased.
The potential energy is always increasing no matter what the temperature is.