Student Exploration: Heat Transfer by Conduction

Name: Kinley Teo Date: 3/20/24 Student Exploration: Heat Transfer by Conduction Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: conduction, convection, insulate, radiation, thermal conductor, thermal energy, thermal insulator Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Suppose two frying pans have been left on the stove with the burners on. One of the frying pans has a metal handle and the other has a wooden handle. 1. Which handle do you think you could safely touch? I think I could safely touch the wooden handle. 2. Why do you think one handle will be cooler than the other? I think the wooden handle will be cooler than the metal because it is a good insulator. Gizmo Warm-up Heat, also called thermal energy, can be transmitted through space (radiation), by moving fluids (convection), or through direct contact. This final method, called conduction, is explored in the Heat Transfer by Conduction Gizmo. To begin, check that Aluminum is selected. Select the BAR CHART tab and turn on Show numerical values. 1. What is the initial temperature of each beaker? Beaker A 2. Click Play ( 95 c Beaker B 5c ) and observe. A.​ What happens to the temperature of Beaker A over time? The temperature of beaker A decreases as heat is transferred to beaker B. B.​ What happens to the temperature of Beaker B over time? The temperature goes up till both beakers are the same temperature. 3.​ Why do you think the temperatures of Beaker A and Beaker B changed as they did? I think the temperatures changed as they did because the aluminum is conductive. Activity A: Get the Gizmo ready: Measuring heat transfer ●​ Click Reset ( ). ●​ Check that Aluminum is selected. Question: How does the temperature difference between two containers relate to the rate of temperature change? 1.​ ✏️ Observe: What does the graph show about the rate of temperature change over time? Both temperatures changed till they were the same. 2.​ Form hypothesis: How do you think the temperature difference between the beakers relates to the rate of heat transfer? I think they swap temperatures till they equal out. 3.​ Gather data: Select the TABLE tab. Click Reset, and then click Play. Click Pause ( ) every 100 seconds (does not have to be exact). Each time you click Pause, record the temperature of each beaker and their temperature difference in the table below. (To find the temperature difference, subtract the temperature of beaker B from that of beaker A.) Time (s) Beaker A temp. (°C) Beaker B temp. (°C) Temp. difference (°C) 0s 95 c 5c 90 c 100 s 77.2 c 22.7 c 54.6 c 200 s 62.6 c 33.4 c 33.2 c 300 s 60 c 40 c 20 c 400 s 56.1 c 43.9 c 122 c 500 s 53.7 c 46.3 c 74 c 600 s 52.2 c 47.8 c 44 c 4. Calculate: At each time, what is the sum of the temperatures in each beaker? 100 c 5. Apply: In this simulation, the beakers are perfectly insulated. This means that no thermal energy (heat) is lost to the outside environment. If the beakers were not perfectly insulated, how do you think the sum of their temperatures would change over time? Explain. The sum would decrease because the temperatures will equal out. eventually. 6. Compare: For each beaker, determine how much the temperature changed in the first 100 seconds and how much it changed between 500 and 600 seconds. Compare this to the temperature difference between the beakers at the start of each interval. Value 0–100 s interval 500–600 s interval Beaker A temperature change 77 c 15 c Beaker B temperature change 77 c 15 c Temperature difference between Beaker A and Beaker B at 0 seconds. 80 c Temperature difference between Beaker A and Beaker B at 500 seconds. 74 c 7. Analyze: How does the rate of temperature change depend on the temperature difference between the two beakers? The closer in temperature the slower the temperature change 8. Think and discuss: Why do you think the rate of temperature change does not stay constant over time? If possible, discuss your answer with your teacher and classmates. I think the rate of temperature change does not stay constant over time because the aluminum affects the temperature change. Activity B: Conductors and insulators Get the Gizmo ready: ●​ Click Reset. ●​ Select the TABLE tab. Introduction: Materials that allow heat to pass through easily are called thermal conductors. Materials that resist the transfer of heat are called thermal insulators. Question: Which materials are the best conductors? Which are the worst conductors? 1.​ Predict: In the Gizmo, you can use aluminum, copper, steel, or glass to connect the two insulated beakers. A. Which material do you think will be the best thermal conductor? copper B. Which material do you think will be the best thermal insulator? glass 2.​ Gather data: With Aluminum selected, click Play. Click Pause after about 200 simulated seconds. Record the temperature of each beaker at 200 seconds. Next, calculate the temperature change of Beaker A. Repeat with each material to complete the table. Material Beaker A temp. at ​ 200 seconds (°C) Beaker B temp. at ​ 200 seconds (°C) Beaker A temp. change (°C) Aluminum 66.6 c 33.9 c 22.4 c Copper 56.9 c 43.1 c 38.1 c Steel 26 c 14 c 9c Glass 99.2 c 52 c 0.2 c 3.​ Analyze: What does your data indicate? Copper is the better conductor and glass is the better insulator. 4.​ Classify: Which materials would you classify as thermal conductors, and which would you classify as an insulator? Which material was the best thermal conductor? Thermal conductors: aluminum steel Thermal insulator: Best thermal conductor: glass copper copper 5.​ Apply: A good frying pan will transfer heat quickly from the stove burner to the food. Based on the results of the Gizmo, which material would be best for frying pans? Why? copper Copper is the best thermal conductor so it would be the best to make a frying pan out of.