Heat and Temperature Experiments | Cheat Sheet Heat and Mass Transfer

Heat and Temperature Experiments

Note: For many of the experiments that follow, you will be using an immersion heater. This device must be covered in a liquid

when it is plugged in. If it is not immersed in a liquid, the device will not dissipate energy quickly enough, and will burn up.

Always immerse the coils of the heater completely in the liquid before plugging it in. Similarly, always unplug the heater before

removing it from the liquid. It is recommended that the immersion heater be plugged into the Kill-A-Watt meter so that you can be

certain that the heater is working at any time during your experiment. Record the power rating at the start of each experiment.

There is a special LoggerPro file designed specifically for each experiment. Make sure that you are using the appropriate file.

Always save the LoggerPro file using the SAVE AS command in your own folder in the Student Documents folder under a name

specific to your lab group. Also save a copy on your USB drive. Do NOT save your data over the master LoggerPro file for the

experiment, and don’t save it on the desktop or in the master experiment folder.

Experiment 1 – Mixing Water Samples

In this experiment, you will

prepare two samples of water, one

at 25°C, and another at 80°C. You

should try to get the masses as

close to the values listed as

possible, and the temperatures

within one degree of the listed

temperature. Each lab group

should do a different trial from

the other lab groups in your class.

Since the 80°C sample will start

to reach equilibrium with the surrounding quite rapidly (especially if the size of the sample is small) you

would be well-advised to start with a sample at a considerably higher temperature and begin data collection

at the instant your sample reaches a temperature of 80°C.

Plug a temperature probe into analog channels 1 and 2. Open the file Exp. 1-Mixing Water Samples. Put

each water sample in a small. Styrofoam cup. Place a temperature probe in each cup. Select the COLLECT

button as soon as Cup B reaches 80°C and take temperature data for about 10 seconds. Then quickly dump

the water from each cup into a large Styrofoam cup while simultaneously moving the temperature probes

from the small cups to the large cup. Stir the mixture until the combined sample reaches an equilibrium

temperature. Print a copy of the resulting temperature vs. time graph for each member of your lab group.

Write your data in the class data table on the board. Obtain the values for the other groups.

What conclusions can you draw from your graph and the collective class data? Once you have established

the overall mathematical model for this set of experiments, calculate the theoretical equilibrium temperature

for each mixture and calculate your error.

Experiment 2 – Heating Water, Different Masses

Open the file Exp. 2-Heating Water. After immersing the coils of your immersion heater in water, record

the power rating of your immersion heater. In this experiment you will start with water at room temperature

whatever temperature it comes out of the tap. Each trial will involve a different amount of water that you

will heat with your immersion heater for equal amounts of time. Use a small Styrofoam cup for the first

trial, and start with 80 g of water. Plug a temperature probe into analog channel 1. Unplug the probe in

channel 2. Place your immersion heater and the temperature probe in the water. Heat the water until it

reaches a temperature of 25°C, and immediately hit the COLLECT button. It is critical that you continually

stir the water vigorously with the immersion heater throughout each experiment. When 60 seconds of data

have been collected, unplug the immersion heater and then remove it from the water. The file will

automatically stop collecting data after 60 seconds. Go to the EXPERIMENT menu and select STORE

LATEST RUN. Record your initial and final temperatures. Dump your water and prepare a 160 g sample of

room temperature water. At some point you will need a larger Styrofoam cup. Repeat the experiment with

the 160 g sample. Continue this process, increasing the sample size by 80 g each trial until you reach 400 g.

Select STORE LATEST RUN after each run. Annotate each line with the corresponding mass. Print the

Heat and Temperature Experiments-R. P. Rice 2012 Page

Mass of Water in

Cup A (~25 °C)

T (°C)

Cup A

Mass of Water in

Cup B (~80 °C)

T (°C)

Cup B

Tfinal (°C)

Cup C

25 g 175 g

50 g 150 g

75 g 125 g

100 g 100 g

125 g 75 g

150 g 50 g

175 g 25 g

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Heat and Temperature Experiments Note: For many of the experiments that follow, you will be using an immersion heater. This device must be covered in a liquid when it is plugged in. If it is not immersed in a liquid, the device will not dissipate energy quickly enough, and will burn up. Always immerse the coils of the heater completely in the liquid before plugging it in. Similarly, always unplug the heater before removing it from the liquid. It is recommended that the immersion heater be plugged into the Kill-A-Watt meter so that you can be certain that the heater is working at any time during your experiment. Record the power rating at the start of each experiment. There is a special LoggerPro file designed specifically for each experiment. Make sure that you are using the appropriate file. Always save the LoggerPro file using the SAVE AS command in your own folder in the Student Documents folder under a name specific to your lab group. Also save a copy on your USB drive. Do NOT save your data over the master LoggerPro file for the experiment, and don’t save it on the desktop or in the master experiment folder. Experiment 1 – Mixing Water Samples In this experiment, you will prepare two samples of water, one at 25°C, and another at 80°C. You should try to get the masses as close to the values listed as possible, and the temperatures within one degree of the listed temperature. Each lab group should do a different trial from the other lab groups in your class. Since the 80°C sample will start to reach equilibrium with the surrounding quite rapidly (especially if the size of the sample is small) you would be well-advised to start with a sample at a considerably higher temperature and begin data collection at the instant your sample reaches a temperature of 80°C. Plug a temperature probe into analog channels 1 and 2. Open the file Exp. 1-Mixing Water Samples. Put each water sample in a small. Styrofoam cup. Place a temperature probe in each cup. Select the COLLECT button as soon as Cup B reaches 80°C and take temperature data for about 10 seconds. Then quickly dump the water from each cup into a large Styrofoam cup while simultaneously moving the temperature probes from the small cups to the large cup. Stir the mixture until the combined sample reaches an equilibrium temperature. Print a copy of the resulting temperature vs. time graph for each member of your lab group. Write your data in the class data table on the board. Obtain the values for the other groups. What conclusions can you draw from your graph and the collective class data? Once you have established the overall mathematical model for this set of experiments, calculate the theoretical equilibrium temperature for each mixture and calculate your error. Experiment 2 – Heating Water, Different Masses Open the file Exp. 2-Heating Water. After immersing the coils of your immersion heater in water, record the power rating of your immersion heater. In this experiment you will start with water at room temperature whatever temperature it comes out of the tap. Each trial will involve a different amount of water that you will heat with your immersion heater for equal amounts of time. Use a small Styrofoam cup for the first trial, and start with 80 g of water. Plug a temperature probe into analog channel 1. Unplug the probe in channel 2. Place your immersion heater and the temperature probe in the water. Heat the water until it reaches a temperature of 25°C, and immediately hit the COLLECT button. It is critical that you continually stir the water vigorously with the immersion heater throughout each experiment. When 60 seconds of data have been collected, unplug the immersion heater and then remove it from the water. The file will automatically stop collecting data after 60 seconds. Go to the EXPERIMENT menu and select STORE LATEST RUN. Record your initial and final temperatures. Dump your water and prepare a 160 g sample of room temperature water. At some point you will need a larger Styrofoam cup. Repeat the experiment with the 160 g sample. Continue this process, increasing the sample size by 80 g each trial until you reach 400 g. Select STORE LATEST RUN after each run. Annotate each line with the corresponding mass. Print the Heat and Temperature Experiments-  R. P. Rice 2012 Page Mass of Water in Cup A (~25 °C)

T (°C)

Cup A Mass of Water in Cup B (~80 °C)

T (°C)

Cup B Tfinal (°C) Cup C 25 g 175 g 50 g 150 g 75 g 125 g 100 g 100 g 125 g 75 g 150 g 50 g 175 g 25 g 1

graph with the five plots. Plot a graph of ∆temperature vs. the mass of the sample. Explain your results. What is the significance of the slope of the graph? Calculate your error for the slope.

Experiment 5 – Heat of Vaporization Open the file Exp. 5-Heat of Vaporization. After immersing the coils of your immersion heater in water, record the power rating of your immersion heater. Enter this value in the parameter control area of the LoggerPro file. Using the same 400 ml beaker of now nearly boiling water from the previous experiment, set up a ring stand so that it will suspend the immersion heater and temperature probe. This can be done with two buret clamps and foam inserts that will allow you to clamp on the cords tightly enough to support them. You’ll need about 200 ml of water to ensure that the coils of the immersion heater are covered throughout the experiment. If you put more than 225 ml, you’ll overload the balance. You want the coils of the immersion heater completely submerged and as close to the bottom of the beaker as possible without touching the bottom or sides of the beaker. The temperature probe should be as deep as possible in the water without touching the bottom or sides of the beaker. Make sure that the temperature probe is not touching the immersion heater. Plug the temperature probe into analog channel 1. Plug the USB cable from the O’Haus Balance into the USB hub. Plug in the immersion heater. When the temperature reaches 90° C, hit the COLLECT button. As the water heats, watch for condensation of water on the clamps or other items above the beaker. Try to prevent the condensed water from entering the beaker. Collect data for 10 minutes after the water reaches the boiling point. Note the Temperature vs. time and the Mass vs. time graphs. What does each of these graphs tell you? When taken together, what do they mean? Make an “energy added” column in the data table, and plot a graph of Mass vs. Energy Added. What is the significance of the slope of this graph? Calculate the error associated with the slope of this graph. Experiment 6 – Heat of Fusion For this activity you will need a balance, an 8 oz. styrofoam cup, a temperature probe, paper towels, warm water and some crushed ice which is near 0°C. Find and record the mass of the styrofoam cup. Fill it halfway with warm (40-45 C) water; then find and record the mass of the cup and water. Get a handful of crushed ice that is as close as possible to 0 °C. Dry the ice as best as you can with the paper towel. Record the temperature of the water in the cup. Plug a temperature probe into analog channel 1. Open the file Exp. 6, 7-Heating Water. (Alternatively, you might already be collecting data for experiment 4 or 5. A second temperature probe can be connected to analog channel 2 to allow you to measure the temperatures for this experiment while you continue to collect data for those experiments). Place the temperature probe in the water sample. Hit the COLLECT button and then dump the ice into the water. Stir the mixture with your temperature probe and record the lowest temperature reached. If you use too much ice, the temperature will fall to 0°C and some ice will remain; should this happen, repeat the experiment with less ice. Find and record the mass of the cup and cold water. Calculations

Determine the mass of the warm water.
Determine the mass of the ice melted (mass of cold water - mass of warm water).
Calculate the temperature change (T) of the warm water.
Calculate the temperature change of the melted ice. Assume that the initial temperature of the melted ice was 0C. 5. Compute the heat lost by the warm water as it cooled. Q = mass  T  4180 J/kg  C
Using the same equation, compute the heat gained by the melted ice as it warmed to the final temperature.
Note that the value obtained in ( 5 ) is larger than that in ( 6 ). What is the difference between these two values? How do you account for this difference?
The heat of fusion is expressed in J/kg. What value did you obtain for the heat of fusion of ice?
Check your textbook to obtain the accepted value for the heat of fusion of ice. Calculate your error.

Experiment 7 – Specific Heats of Metals Record the mass of each of your five metal samples. Hang the immersion heater over the edge of a 400 ml beaker. Fill the beaker with enough water to completely cover the coils of the immersion heater and so that the water will completely cover the aluminum sample (the tallest cylinder). When the appropriate amount of water is in the beaker, plug in the immersion heater. Determine the mass of the minimum amount of water that can completely cover the aluminum sample in the special insulated vessel. For each trial, put this amount of room temperature water in the vessel at the start of the experiment. Use the Logger Pro file Exp. 6, 7-Heating Water. Record the temperature of the water in the vessel as well as the temperature of the water in the boiler. Using a string connected to the hook, suspend the metal sample in the boiler long enough that you are confident that it has reached the temperature of the boiling water. (Since you are using metal samples, and metals have high thermal conductivities, this should take less than one minute.) Quickly transfer the metal sample from the beaker to the water in the vessel. Stir the water with the temperature probe until the water temperature peaks out. Record the highest temperature reached by the water. Repeat this process for each of the five metal samples. Look up the specific heats for each of the metals used in the experiment. (Aluminum, copper, zinc, lead, and tin). Based on the specific heat of water, determine the energy gained by the water (and therefore lost by the metal) in each trial. Plot a graph of the energy lost/∆T for the metal vs. the specific heat of the metal. What is the significance of the slope of the graph? Explain the concept of specific heat as it relates to this experiment. Experiment 8 – The Mechanical Equivalent of Heat Carefully measure the mass and temperature of the lead shot in your cardboard tube. Replace the stoppered thermometer with a rubber stopper. Measure the distance from the top of the lead shot to the bottom of the stopper on the top of the tube. This is the distance the lead shot will fall with each inversion of the tube. Replace the rubber stopper in the end of the tube. Quickly invert the vertically held tube, 100 times, allowing the lead shot to fall the length of the tube in each inversion. After the 100th^ inversion, replace the rubber stopper with the stoppered thermometer and measure the final temperature of the lead shot. Based on the specific heat of lead and the other variables you have measured, determine the thermal energy gained by the lead. How does the thermal energy gained by the lead compare to the mechanical energy lost by the lead? Are they the same? Why or why not? Writeup Notes This laboratory should be written up as a series of eight individual experiments, each with its own description, diagram, data section, error analysis and conclusion. The eight experiments should be tied together with a final conclusion that unites all of the various parts of the experiment together with an overarching big idea. You should describe in your own words the purpose of and a brief general procedure of each experiment. You can cut and paste the specific procedure from this document into your lab report. If you do this, make sure you cite the source. You may also use the diagrams from Jim An’s lab diagram document if you credit him for the diagrams. MS Word versions of these documents are available from my website.

Heat and Temperature Experiments, Cheat Sheet of Heat and Mass Transfer

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T (°C)

T (°C)