Cool Science: Building and Testing a Model Radiator Mark as Favorite (16 Favorites)
LAB in Calorimetry, Heat, Specific Heat, Temperature, Exothermic & Endothermic, Scientific Method, Graphing, Experimental Design, Chemistry of Cars. Last updated April 20, 2022.
Summary
In this lab students construct a model of a car radiator to investigate parameters that lead to efficient cooling. Students investigate multiple variables as they experiment with various radiator designs. This lesson focuses on thermochemistry calculations and engineering practices.
Grade Level
Middle and high school
NGSS Alignment
This lab will help prepare your students to meet the performance expectations in the following standards:
 HSPS31: Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known.
 HSPS34: Plan and conduct an investigation to provide evidence that the transfer of thermal energy when two components of different temperature are combined within a closed system results in a more uniform energy distribution among the components in the system (second law of thermodynamics).
 HSPS32: Energy cannot be created or destroyed—only moves between one place and another place, between objects and/or fields, or between systems.
 HSETS12: Design a solution to a complex realworld problem by breaking it down into smaller, more manageable problems that can be solved through engineering.
 HSETS14: Systems and System Models:Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows— within and between systems at different scales.
 Scientific and Engineering Practices:
 Using Mathematics and Computational Thinking
 Analyzing and Interpreting Data
 Planning and Carrying Out Investigations
 Constructing Explanations and Designing Solutions
AP Chemistry Curriculum Framework
This lab supports the following unit, topic, and learning objective:
 Unit 6: Thermodynamics
 Topic 6.4: Heat Capacity and Calorimetry
 ENE2.D: Calculate the heat q absorbed or released by a system undergoing heating/ cooling based on the amount of the substance, the heat capacity, and the change in temperature.
Objectives
By the end of this lab, students should be able to
 Calculate calories/joules of heat absorbed by/lost from a liquid of known specific heat.
 Delineate factors that improve the efficiency of a heat exchanging device.
 Create a graph of temperature vs. time (a cooling curve) and interpret its meaning.
 Design controlled experiments that accurately determine the effect of a particular variable.
Chemistry Topics
This lab supports students’ understanding of
 Thermodynamic calculations
 Specific heat values
 Engineering design
 Molecular kinetic energy
Time
Teacher Preparation
2 hours for initial preparation of materials. After the initial constructions/purchases have been made, 3040 minutes of setup time required.
Lesson
 Engage: 10 minutes
 Explore: 50  100 minutes
 Explain: 20  30 minutes
 Elaborate: 20 minutes
 Evaluate: 20  60 minutes
Materials
For each lab group
 5feet of ¼inch copper tubing (sold at hardware stores such as Home Depot)
 One plastic funnel: 4 inch diameter with ¼ inch diameter stem
 One clamp or stopcock valve
 One ring stand (at least 24 inch tall, 36 inch recommended)
 Wire for twist ties
 One plastic pitcher or beaker (500 or 1000 mL recommended)
 250 mL of 50% Propylene glycol solution (or ethylene glycol solution) dyed green using food coloring
 A plastic or glass container to capture the cooled liquid
 A fan
 Unlimited quantities of aluminum foil
 Scale
 Thermometer
Safety
 Always wear safety goggles when handling chemicals in the lab.
 Students should wash their hands thoroughly before leaving the lab.
 When students complete the lab, instruct them how to clean up their materials and dispose of any chemicals.
 Ethylene glycol can be highly toxic for sensitive individuals. Propylene glycol is a safer alternative.
 Students will heat water to scalding temperatures. Caution will be required when pouring and transporting hot liquids.
Teacher Notes
 This resource could be used as a postAP Chemistry exam activity.
 Engage: Use this video that investigates the cooling system of a car. It introduces the need for removal of engine heat and discusses mechanisms used in a car engine to exchange heat with the environment. Chemical components of automotive coolant solutions are also discussed.
 Explore: The heart of this activity is the experimentation that students do with various radiator designs. Students should perform at least three trials using variations in design/materials. Each trial will take about 15 minutes to perform, including setup and collection of data. The teacher should encourage students to discuss which variables they would like to test and how the experiment can be designed to focus on a single variable in each trial. Variables include the use of water vs. a propylene glycol solution, the rate of fluid flow through the model radiator, the use of a fan, and a variety of copper tubing designs (helix vs. coil vs. boustrophedonic (intestine) designs).
 Explain: After performing several trials, students will calculate the efficiency of each design and develop scientific explanations for why some designs were more effective.
 Elaborate: Ideally, students will be able to generalize from their specific results to discover general truths. Students should be encouraged to look at radiators in real cars to see whether the general truths they propose are borne out in professional radiator designs.
 Evaluate: This activity is structured so that students will produce a written report of their findings, including graphs, calculations, and answers to analysis questions. It is possible that the teacher will want students to explain their findings to their classmates using posters or presentations.
 Preparation of materials: Two videos are available to help construct the model radiators used in this lab activity. A class set of copper tubing modules can be created in about 1hour.
 This project uses 5foot lengths of copper tubing bent into various shapes as shown below. A 50foot roll of ¼ inch copper tubing at Home Depot will cost around $40.
 The images above, from left to right, represent the intestine design, the helix design and the spiral design.
 The copper tubing acts as a heat exchanger. The conductivity of the copper helps to disperse the heat of the water into the atmosphere.
 At the top of the radiator module, the copper tubing is connected to a 4 inch funnel using a short segment of ¼ inch Tygon tubing. The copperTygon junction should be secured with a twist tie made of wire. A 4 inch funnel has a capacity of 250 ml.
 At the bottom of the copper tubing module, a 1mL plastic syringe can be cut and inserted into a segment of Tygon to allow for easy connection of a stopcock. Alternatively, a Hoffman style clamp can be used to control the flow rate.
 A tall ring stand is used to support the design. The funnel should be supported using a 3” ring clamp. An additional clamp should be used to support most of the weight of the copper tubing.
 I recommend creating a solution of 50% propylene glycol using stock propylene glycol from Flinn Scientific. This solution can then be dyed green using normal food coloring. It is possible to use commercial antifreeze solutions in place of a homemade solution, but the commercial products will contain an anticorrosion molecule (tolyltriazole) that has an unpleasant, fishy odor (when heated). Using pure propylene glycol (or ethylene glycol) allows for an odorfree experiment. If a commercially available antifreeze is chosen, Sierra brand is propylene glycol based. Other commercial antifreeze solutions are likely to utilize ethylene glycol.
 Sample data collected by the author using various designs is shown below.

This video shows students collecting and analyzing data from their radiator trials.

Teachercollected data from radiator design tests:
Feb 16 (Ambient temp = 23°C) and Feb 17, 2016 (Ambient temperature = 21°C)
Date 
Module 
Fan? 
Volume of water 
Flow through time 
Initial temp 
Final temp 
ΔT 
% Cooling Efficiency 
2/16 
Helix 
No 
300 mL 
3 min 
68.6°C 
53.0°C 
15.6°C 
34% 

Helix 
Yes 
250 mL 
4 min 
68.0°C 
41.4°C 
26.6°C 
59% 

Spiral 
Yes 
250 mL 
? 
70.0°C 
41.4°C 
28.6°C 
61% 
2/17 
Intestine (flattened) 
Yes 
250 mL 
5+ min 
68.0°C 
35.8°C 
32.2°C 
69% 

Intestine (flattened) 
Yes 
250 mL 
4:30 
68.7°C 
37.0°C 
31.7°C 
66% 
Time  Temp °C  Notes 
0  70.1 

30 sec  69.4 

60 sec  68.3  Stirred prior to temp reading 
90 sec  67.7 

120 sec  66.6  Stirred prior to temp reading 
150 sec  66.0 

180 sec  65.0  Stirred prior to temp reading 
210 sec  64.4 

240 sec  63.4  Stirred prior to temp reading 
270 sec  63.0 

300 sec  62.0  Stirred prior to temp reading 
Passive Cooling Efficiency = 17% 
For the Student
Download all documents for this lab, including the Teacher Guide, from the "Downloads box" at the top of the page.