Type lab report and include:

1)Title of the Experiment

2)Introduction/Purpose. It should be about half of a page long, and describe what was the purpose of the experiment,which specific physics laws and concepts the experiment was related to, and what you were expected to observe in the experiment.

3)Validated data sheets obtained in the lab. (You do not need to retype them), and neatly written calculations, including all equations you used.

4) Conclusion should be abouthalf of page long. You should describe your main experimental results and explain whether these results were in an agreement or in disagreement with theoretical predictions. Be specific and provide "some numerical values" obtained in the lab.

T4a: Thermal Expansion Introduction: When having problems opening a glass jar with a metal lid because it is too tight, a good solution would be running hot water over the lid. Why would hot water help you to open the jar?. Most materials expand somewhat when heated through a temperature range that does not produce change in phase. The added heat increases the average amplitude of vibration of the atoms in the material, which increases the average separation between atoms. Since the metal expands more than the glass when heated, the lid will loosen easily. The focus of this experiment is on learning how different materials are affected by changes of temperature. The intrinsic characteristic of materials that determine its capability to expand in one dimension under heat exposure is called "coefficient of linear expansion". On this experiment, a thermal expansion apparatus will be used to measure the coefficient of linear expansion for brass, copper and aluminum. Apparatus: >Thermal expansion apparatus. Steam Generator Steam generator Temperature sensor Meter stick >Glass cup > Computer with Thermal Expansion Apparatus Pasco Capstone Temperature Sensor Software >Heat resistant gloves Meter Stick Figure 1. Experimental SetupTheoretical Background: Most materials expand when heated and contract when cooled. The increase in any one dimension of a solid is called linear expansion. If a rod of length 1.4. and initial temperature Tu undergoes a temperature change of a reasonably small magnitude of AT, the change in length, AL, is generally proportional to L0 and Ni". Stated mathematically: M. = 5:1.ng (1) Here a is called the coefficient of linear expansion for the material with common units of 1/E = (C)'1. Then, solving equation 1, the coefficient of linear expansion will be given by: 15!. (I m (2) Different materials with the same initial length expand and contract by different amounts as the temperature changes, so the value at depends on the nature of the material. For materials that are not isotropic, such as an asymmetric crystal for example, ct can have a different value depending on the axis along which the expansion is measured. The coefficient [r cart also vary somewhat with temperature so that the degree of expansion depends not only on the magnitude of the temperature change, but on the absolute temperature as well. In this experiment, you will measme ct for aluminum, brass, and copper. These metals are isotropic. that niearis or needs only be measured along one direction. Also, within the limits of this experiment, a does not vary with temperature. The materials and corresponding values of the coefficient of linear expansion, reported by the manufacturer, for the metal tubes used on this experiment can be found in Table 1. Table 1. Accepted values for the coefficient of thermal expansion. at. Material a.(t'."1) Composition (%) A1 (95.8 98.6), Mg {0.30 1.2), Fe (was), Si (0.40 _ 0.30) Brass (c270) germ-5 Brass [153 53.5), Zn (31.3 3r), Pb (0.1), Fe {0.07) Copper ((3122) \"0,104 Cu (99.9), P (0.02 nominal) Aluminum (lT) 2.36 '10'5 Date Modied 08mm!) 2 Procedures: WARN ING! HIGH TEMPERATURE The metal tube gets hot during the experiment. Steam can cause burns. Do not touch the me tal tube during operation. 1. Take the rubber lid off from the Steam Generator. Fill the oneliter tank approximately NZ to 3% full of water using the auxiliary cup and place the rubber stopper over the top. Two long plastic tubes should be attached to the rubber stopper with one blocked with a tubing clamp. Place the free plastic tube inside of a separate ask while not using it and place the flask near to the right side of' the apparatus. Do not connect the plastic tubing to the metal tubes yet! You will do it later when you get approved by a lab assistant. Turn ON the Steam Generator and set the dial from LOW to HIGH. It will take between 10 to 15 minutes to bring the water from room temperature to boiling. While the Steam Generator heats up the water, measure the length L of the three metal tubes at room temperature with the provided meter stick. Measure from the inner edge of the larger circular disk on one end to the inner edge of the smaller circular disk at the other end. Make sure the meter stick is straight when measuring the rod. Record the lengths on Data Table 1. Mount the aluminum tube in the apparatus frame as shown in Figure 2, with the larger disk to your left and the smaller disk to your right. The larger disk of the rod presses against the tip of the spring arm of the dial indicator, while the smaller disk ts into a slot on the right side of the apparatus. Tubing Adapter Digital Indicator Phone Plug Figure 2. Turn the aluminum metal tube so that the thermistor lug under the foam insulation is on top. Connect the phone plug into the phone jack of the temperature sensor. Tighten up the thumb-screw in the right end of the apparatus frame against the tube to lock it. Make sure that the foam insulator is centered over the thermistor lug. Connect the PASCO Thermal Sensor to the computer. Date Modied USIUISIZO 3 9. Turn ON the computer and open the T4a experiment software. The le is located in the experiments folder. 10. Press the ONIOFF button on the digital indicator to turn it on. Press the ZERO button to set the initial digital reading to zero. 11. Press the record button in the computer software to begin recording the temperature of the aluminum rod. Leave the record button on. 12. Verifyr with a lab assistant that your set up is correct before you continue to next steps. 13. Wear disposable gloves and the heat resistant gloves on top. 14. Once the free plastic tubing inside the separate ask begins pouring water vapor, carefully take it out aftheask and stick it on the aluminum rod. 15. Once the steam starts owing through the tube, you will be able to observe the temperature change in the computer and the digital indicator will reflect the length that the metal tube has expanded. Once the nal temperature stabilizes and the value displayed in the digital indicator doesn't change, stop the data collection and record the change in length. AL, on Data Table l. 16. Using the protecting gloves remove the plastic tubing from the right side of the metal tube and place it back to the auxiliary glass. 1?. Disconnect the phone plug from the temperature sensor. Untighten the thumbscrew that is holding the aluminum tube to the apparatus frame and carefully remove it. Be careful to not burn yourself; the tube might contain hot water vapor inside. Place the hot tub in the sink. 18. Ask a lab assistant for instructions using the Pasco Capstone software and nd the beginning and ending temperature. Record your values on Data Table 1. 19. Repeat steps 4 to 18 with the other metal tubes. 20. Turn of the steam generator. 21. Calculate the change of temperature for all metal rods. 22. Calculate the experimental coe fficients of thermal expansion at. 23. Compare your calculated values of D: with the theoretical values registered on Table 1 and calculate the percentage errors. 24. Answer the questions. Data Sheets: T4a: Thermal Expansion NAME: Gones's Almaden Bus DATE: 3 / 22 / 23 Change of Thermal Tube Initial Initial Final Temperature Change expansion Percent Material Length Temperature Temperature of Coefficient Error (m) ('C) ("C) length (m) ( c - 1 ) Aluminum 0. 730 23. 039 97.469 74. 43 0 001 36 2. 43629 13. 2 3 3 Brass 6. 6750 23.031 98. 602 75. 571 200 11 1 940 7 6-05 9 395 Copper 6..)734 23. 670 98 509 173.43 . 100 98 1.73 2490 EDS 1. 989 Questions: 1) Which of the three materials has the largest coefficient of thermal expansion? Aluminium 2) Why do you think civil engineers leave gaps between segments, in a bridge or in a concrete wall? becage (because the heat - To prevent exta pressure. between Segments in a bridge. Becasse of the Physics Lab heat MAR 2 2 2023 Date Modified 08/06/20 Valencia College WC