Lesson: Hot Potato, Cool Foil

Quick Look

Grade Level: 11 (9-12)

Time Required: 1 hours 30 minutes

(can be split into two 45-minute sessions)

Lesson Dependency:

Subject Areas: Chemistry, Physics

A colorful drawing of a red-hot spacecraft above a blue-layered atmosphere.
Figure 1. An artist's conception of the shuttle re-entering the atmosphere. Friction with the air causes the shuttle's outer surface to heat substantially.
copyright
Copyright © 2008 National Aeronautics and Space Administration http://www.nasa.gov/centers/ames/multimedia/images/2006/shuttlehistory.html

Summary

Students explore material properties by applying some basic principles of heat transfer. They use calorimeters to determine the specific heat of three substances: aluminum, copper and another of their choice. Each substance is cooled in a freezer and then placed in the calorimeter. The temperature change of the water and the substance are used in heat transfer equations to determine the specific heat of each substance. The students compare their calculated values with tabulated data.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Engineering Connection

All engineers must know the properties and tolerances of the materials they are using in a project, whether it be the reaction temperature in a chemical process, the strength of a composite material in airplanes, the steel in a bridge, or the temperature tolerances in an engine. In particular, NASA has to know the tolerances and properties of the materials engineers use to build space vehicles. The heat shield is a good example. Engineers have to be able to predict how much the heat shield will expand, how hot it will get, and how quickly it will wear down using the various material properties. Heat capacity is one of these important properties, and can be determined using basic knowledge of heat transfer.

Learning Objectives

After this activity, students should be able to:

  • Explain that heat capacity is the amount of heat a quantity of a substance can absorb/release when changing by one unit temperature.
  • Explain that material properties and tolerances are important in the design and construction of engineering projects in order to assure functionality and safety as well as exploit a substance's natural abilities to solve a problem.

Educational Standards

Each TeachEngineering lesson or activity is correlated to one or more K-12 science, technology, engineering or math (STEM) educational standards.

All 100,000+ K-12 STEM standards covered in TeachEngineering are collected, maintained and packaged by the Achievement Standards Network (ASN), a project of D2L (www.achievementstandards.org).

In the ASN, standards are hierarchically structured: first by source; e.g., by state; within source by type; e.g., science or mathematics; within type by subtype, then by grade, etc.

NGSS Performance Expectation

HS-PS3-1. 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. (Grades 9 - 12)

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This lesson focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Create a computational model or simulation of a phenomenon, designed device, process, or system.

Alignment agreement:

Energy is a quantitative property of a system that depends on the motion and interactions of matter and radiation within that system. That there is a single quantity called energy is due to the fact that a system's total energy is conserved, even as, within the system, energy is continually transferred from one object to another and between its various possible forms.

Alignment agreement:

Conservation of energy means that the total change of energy in any system is always equal to the total energy transferred into or out of the system.

Alignment agreement:

Energy cannot be created or destroyed, but it can be transported from one place to another and transferred between systems.

Alignment agreement:

Mathematical expressions, which quantify how the stored energy in a system depends on its configuration (e.g. relative positions of charged particles, compression of a spring) and how kinetic energy depends on mass and speed, allow the concept of conservation of energy to be used to predict and describe system behavior.

Alignment agreement:

The availability of energy limits what can occur in any system.

Alignment agreement:

Models can be used to predict the behavior of a system, but these predictions have limited precision and reliability due to the assumptions and approximations inherent in models.

Alignment agreement:

Science assumes the universe is a vast single system in which basic laws are consistent.

Alignment agreement:

  • Solve systems of linear equations exactly and approximately (e.g., with graphs), focusing on pairs of linear equations in two variables. (Grades 9 - 12) More Details

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  • Rearrange formulas to highlight a quantity of interest, using the same reasoning as in solving equations. (Grades 9 - 12) More Details

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  • Energy can be grouped into major forms: thermal, radiant, electrical, mechanical, chemical, nuclear, and others. (Grades 9 - 12) More Details

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  • Materials have different qualities and may be classified as natural, synthetic, or mixed. (Grades 9 - 12) More Details

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  • Solve linear equations and inequalities in one variable, including equations with coefficients represented by letters. (Grades 9 - 12) More Details

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  • Reason quantitatively and use units to solve problems. (Grades 9 - 12) More Details

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  • Use appropriate measurements, equations and graphs to gather, analyze, and interpret data on the quantity of energy in a system or an object (Grades 9 - 12) More Details

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  • Use direct and indirect evidence to develop predictions of the types of energy associated with objects (Grades 9 - 12) More Details

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Worksheets and Attachments

Visit [www.teachengineering.org/lessons/view/cub_heat_lesson1_activity2] to print or download.

More Curriculum Like This

Heat Transfer: From Hot to Not

Students learn the fundamental concepts of heat transfer and heat of reaction. This includes concepts such as physical chemistry, an equation for heat transfer, and a basic understanding of energy and heat transfer.

Pre-Req Knowledge

Algebra: Students need to know how to perform basic algebraic manipulation of equations and substitution techniques.

Physical Science: Students should be familiar with the concept of energy, that it can be exchanged, and that it comes in different forms.

Introduction/Motivation

Different materials hold different amounts of heat. For example, think of a baked potato wrapped in aluminum foil freshly removed from an oven. Initially, both the potato and the foil are at the same temperature, the oven temperature. However, after several minutes exposed to the room temperature air, there is a large difference in temperature between the foil and the potato. The potato is still very hot, whereas the aluminum foil has already cooled to the ambient air temperature.

Why is this? Many factors contribute to this interesting phenomenon, but what we are interested in is the specific heat, or heat capacity. Heat capacity is the amount of energy a substance can absorb while increasing in temperature. Objects with a high heat capacity can absorb a lot of energy before getting hotter, while things with a low heat capacity only need a little energy before changing temperature. Since the aluminum has a lower heat capacity, it contains less energy and thus cools more quickly to room temperature. Our baked potato on the other hand has a higher heat capacity, and has a lot more energy to release before it cools down again.

Understanding this phenomenon is an important part of engineering. By understanding this and other material properties, engineers ensure the materials they are working with stay safe and are reliable. Aerospace and mechanical engineers need to know the amount of heat a material can absorb in a space vehicle or automobile in order to ensure it does not overheat and explode or disintegrate. Chemical and biological engineers need to know how much energy it will take to heat substances to an appropriate reaction temperature for ideal chemical or biological synthesis. Other engineers can use this information for everything from cooling systems in buildings to operating temperatures in circuits. Knowledge of heat capacity is obviously a very important connect for engineering.

Vocabulary/Definitions

enthalpy: A value which describes the amount of energy in a system including pressure and volume, relative to a reference state.

heat: Energy transferred between two systems as a result of a temperature difference.

heat capacity: The amount of energy transfer required to raise or lower a given amount of a substance by one unit temperature at a constant pressure.

Assessment

Pre-Activity Assessment

Accessing Prior Knowledge: Have the students complete the Do You Have the Capacity? Worksheet to start them thinking about heat capacity. Review their answers to gauge their mastery of the subject.

Activity Embedded Assessment

Worksheet: Have the students follow along with the As Cold as Ice Worksheet. Review their answers to gauge their mastery of the subject.

Post-Activity Assessment

Reflection: Have the students complete the To Heat or Not to Heat Worksheet. On this worksheet, they calculate the accuracy of their calculations as well as suggest improvements for the next iteration of the design. Have them share their ideas with the class. Review their answers to gauge their mastery of the subject.

Lesson Extension Activities

Have students go online or to a library to learn more about heat capacity and specific heat. For example, find equations describing how heat capacity can be calculated for different temperatures or how it changes with temperature. Also, the students should report on why different substances hold more heat than others.

References

Dino, Jonas, National Aeronautics and Space Administration, "25 Years of Space Shuttle History in Pictures," March 29, 2008, accessed December 2, 2009. http://www.nasa.gov/centers/ames/multimedia/images/2006/shuttlehistory.html

Copyright

© 2009 by Regents of the University of Colorado.

Contributors

James Prager; Megan Schroeder; Malinda Zarske; Janet Yowell

Supporting Program

Integrated Teaching and Learning Program, College of Engineering, University of Colorado Boulder

Acknowledgements

The contents of this digital library curriculum were developed under a grant from the Fund for the Improvement of Postsecondary Education (FIPSE), U.S. Department of Education and National Science Foundation GK-12 grant no. 0338326. However, these contents do not necessarily represent the policies of the Department of Education or National Science Foundation, and you should not assume endorsement by the federal government.

Last modified: August 22, 2018

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