Lab Report 1

Katie Elmer Physics Honors-7 February 20, 2007 Partner: Tina Chen Lab Report: Heating Curve of Water Purpose: We will heat ice that has been frozen in a test tube and watch what happens to the temperature as we constantly add heat. Materials: •

Hot plate

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400mL beaker

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CBL

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Calculator with PHYSICS or CHEMBIO programs

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Link cord

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DIN adapter

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Power supply

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Temperature probe frozen in test tube

Procedure: 1. Assemble all your equipment. The probe should be the last thing you get. 2. Plug the probe into Channel 1, turn on the CBL, and enter PHYSICS program. 3. SET UP PROBES-ONE-TEMPERATURE-USE STORED CALIBRATION. 4. COLLECT DATA-TIME GRAPH-10 seconds between samples-90 samples-USE TIME SETUP. 5. LIVE DISPLAY. 6. Ymin=-10

Ymax=100

7. Place beaker on hotplate. Turn hotplate to high. Start collecting data.

8. BE VERY CAREFUL NOT TO LET THE PROBE CORD TOUCH THE HOTPLATE! Apparatus:

Precautions: Whenever working with boiling substances, make sure always wear safety goggles so that the liquids do not splash into your eyes and harm you. Make sure that nothing surrounding the hotplate is flammable, or will melt easily. It may even be safer to wear heat-resistant gloves. Data: See attached graph. Analysis: 1. See graph. 2. See graph 3. The region indicated by the heating of ice has a greater slope. The specific heat capacity of ice is higher than that of water, so it makes sense that that area would have a greater slope. 4. On regions b. and d., the temperature does not go up because the heat energy is being used to make the substance change state. Error Analysis: In the graph, there are times where the line makes an unexpected jump of fall. This is because the substance does not heat at the same rate. If the temperature probe shifts a little and touches a cold or hot patch, it will throw off your data. This is a random error. The air temperature will unevenly heat or cool the water. It can skew the data. This is a systematic error. If there was an unexpected tornado, the classroom would have exploded, and the data would not come out right. This is a very random error. Fortunately, there were no tornadoes when we did our lab. Conclusion:

I found what the heating curve of water looks like. I also learned that the specific heat capacity of a substance correlates to the graph or that substance’s heating curve. Lastly, I learned what a change in state looks like when you record the change in temperature of the substance.