Measuring Heat-Flow Rate Incorporating LabPro™ Interface

Ms. Kimberly Biggs Technology Education Principles of Technology I Grades Chatham High School

Lab 3T2 Measuring Heat-flow Rate pg This lab allows students to investigate the the heat-flow rate of various materials. Students should be able to observe that heat-flow rate is effected by thermal conductivity, surface area, temperature difference and material thickness. Student will measure and compare Steady- state input and output.

Competencies 12. Describe what is meant by rate in general and in mechanical, fluid, electrical, and thermal systems. 13. Identify appropriate SI and English units for rate in all four energy systems. 14. Measure rate in mechanical, fluid, electrical and thermal systems. 15. Identify workplace applications where rate is measured and/or controlled.

Objectives When you’ve finished this lab, you should be able to do the following: –1. Describe how the heat-flow rate across two faces of an object depends on: a. thermal conductivity of the material in the object. b. surface area of the faces. c. temperature difference between the two faces. d. material thickness between the two faces.

–2. Set up a lab experiment to measure the effect of thermal conductivity and surface area on heat-flow rate. –3. Use the formula, Q H = kA  T to calculate heat-flow rate through l a given object.

Materials Equipment list for lab 3T2 page 119 Vernier Probe ware Logger Pro software and interface 2 or 3 Temperature probes

Getting Started The setup up for the lab will be the same as described in the text, except for the placement of the temperature probes.

Place Temperature probes as shown. A hole (11/64”) must be drilled in the insulated lids, be sure to drill so that the lid will still fit on the Delwar Flask with the probe inserted. You may also use a third probe to measure room temperature.

Setting up the LabPro™ Interface Before opening the Logger Pro software you should connect the interface to the computer. Also connect the power and insert the probes that you will be using. When you open the software the interface connection will be tested. If you open the software before connecting the interface close the program and open it when all connections have been made.

Collecting Data Once the lab setup is complete and you are ready to collect data, open the Logger Pro software, the software will check the connection with the interface. Follow screen prompts to correct any problems that occur with the interface. From the menu bar click “Experiment” and then “Sampling” from this window you will be able to set the length of the experiment and how often data is collected.

When you are ready to collect data click on “Collect” and this will start your data collection. You will be able to see a graph and table of the data as it is collected.

Once you have collected the data the file can be saved or exported in spreadsheet software. The data can also be analyzed using the Logger Pro software.

Assessment I thought that the lab was much more interesting with the probes and interface. Although the result were not accurate, the lab itself did not expect to obtain matching values, I feel that with some changes with probe location better results will be obtained. I think that getting results of the data immediately will help students to understand the lab activities.