Heating and Cooling of a Pure Substance experiment

Last class was when we did the heating and cooling of a pure substance.  The materials used were a pair of safety goggles, a test tube with the pure substance, a beaker with warm water, 2 thermometers, a mini stove like device, and a device that held the test tube that could also adjust to move the test tube up or down. 

The Cooling Process

The test tube was adjusted on the device and lowed into a beaker of room temperature water.  In every 30 seconds, the thermometer would either drop quickly or slowly.  The original temperature of the pure substance was 45 degrees.  The purpose was to see how long it would take for the substance to have a temperature of 25 degrees.  The whole process was to be recorded on the pre drawn table.  Next was the heating process.

The Heating Process

By now the pure substance should be a solid from the cooling process.  The next step was to bring out the mini stove like device and place a beaker of water on top of it.  The mini stove like device has a nob which was turned to 200 for the amount of heat used.  By now the substance's test tube is 25 degrees.  Place it in the beaker that is sitting on top of the mini stove like device.  The result should be a increase of temperature.  The temperature may move rapidly or slowly depending on how cold the water of the beaker is.  The temperature was to be recorded every 30 seconds until the temperature of the pure substance reached 50 degrees.  When the temperature reaches close to 50 degrees, the pure substance should start to change state.  By 50 degrees, the pure substance would be completely dissolved.  By the end of the heating process, your table should have the amount of time it took to reach the required temperature of both the heating and cooling processes.  When you have both of them, clean up the station and move onto the lab report.