Unit Overview
6.2 Thermal Energy

How can containers keep stuff from warming up or cooling down?

Unit Summary

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This unit on thermal energy transfer begins with students testing whether a new plastic cup sold by a store keeps a drink colder for longer compared to the regular plastic cup that comes free with the drink. Students find that the drink in the regular cup warms up more than the drink in the special cup. This prompts students to identify features of the cups that are different, such as the lid, walls, and hole for the straw, that might explain why one drink warms up more than the other.

Students investigate the different cup features they conjecture are important to explaining the phenomenon, starting with the lid. They model how matter can enter or exit the cup via evaporation However, they find that in a completely closed system, the liquid inside the cup still changes temperature. This motivates the need to trace the transfer of energy into the drink as it warms up. Through a series of lab investigations and simulations, students find that there are two ways to transfer energy into the drink: (1) the absorption of light and (2) thermal energy from the warmer air around the drink. They are then challenged to design their own drink container that can perform as well as the store-bought container, following a set of design criteria and constraints.

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STUDENT VIDEOS
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Unit Examples

Simulations

Cup Design – Particle Heating and Cooling Simulation

This simulation allows students to make observations about how particle motion changes as the overall temperature of a liquid changes. It is used in Lesson 11 of Unit 6.2.

Cup Design – Molecular View of a Liquid

This simulation allows students to make observations about the structure and movement of particles in a liquid. It is used in Lesson 11 of Unit 6.2.

Cup Design – Molecular View of a Gas

This simulation allows students to make observations about the structure and movement of particles in a gas. It is used in Lesson 11 of Unit 6.2.

Cup Design – Gas Particle Motion

This simulation explores the relationship between the temperature of a gas, the motion of the particles in the gas and the changes in the kinetic energies of particles during collisions. It is used in Lesson 12 and Lesson 13 of unit 6.2.

Cup Design – Conduction in Solids Reduced

This simulation shows conduction of thermal energy within and between solids, based on the kinetic energy of particles, and collisions between neighboring particles. It is used in Lesson 13 of Unit 6.2.

Cup Design – Conduction in Solids Full

This simulation shows conduction of thermal energy within and between solids, based on the kinetic energy of particles, and collisions between neighboring particles. It is used in Lesson 13 of Unit 6.2. This simulation differs from the “reduced” version in that it has expanded controls over the variables.

Cup Design – Collisions Up Close

This simulation explores the relationship between particle kinetic energies during particle collisions. It is used in Lesson 13 of Unit 6.2.

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Additional Unit Information

Building Toward the Following Standards and Practices
Performance Expectations

This unit builds toward the following NGSS Performance Expectations (PEs): 

  • MS-PS1-4*: Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.
  • MS-PS3-3: Apply scientific principles to design, construct, and test a device that either minimizes or maximizes thermal energy transfer
  • MS-PS3-4: Plan an investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample
  • MS-PS3-5: Construct, use, and present arguments to support the claim that when the kinetic energy of an object changes, energy is transferred to or from the object.
  • MS-PS4-2*: Develop and use a model to describe that waves are reflected, absorbed, or transmitted through various materials.
  • MS-ETS1-4: Develop a model to generate data for iterative testing and modification of a proposed object, tool, or process such that an optimal design can be achieved.

*These performance expectations are developed across multiple units. This unit reinforces or works toward these NGSS PEs that students should have previously developed or will develop more fully in future units. In the OpenSciEd Scope and Sequence, PS4-2 is first built in Unit 6.1. In this new context of particle models and energy transfer, students learn more about how absorption of light occurs at the particle level. This unit begins to address changes in state that are part of PS1-4; then changes in state are more fully developed in the next unit, 6.3, on water cycling. In 6.3, students learn that evaporation and condensation occur when energy is added or removed from the substance.

Disciplinary Core Ideas

The unit expands students’ understanding of particle models and energy transfer, which include these Grade 6–8 DCI elements: 

PS1.A: Structure and Properties of Matter

  • Gases and liquids are made of molecules or inert atoms that are moving about relative to each other. (MS‑PS1‑4)
  • In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and may vibrate in position but do not change relative locations. (MS‑PS1‑4)
  • The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter. (MS‑PS1‑4)

PS3.A: Definitions of Energy

  • The term “heat” as used in everyday language refers both to thermal energy (the motion of atoms or molecules within a substance) and the transfer of that thermal energy from one object to another. In science, heat is used only for this second meaning; it refers to the energy transferred due to the temperature difference between two objects. (secondary to MS‑PS1‑4)
  • Temperature is not a measure of energy; the relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter present. (secondary to MS‑PS1‑4)
  • Temperature is a measure of the average kinetic energy of particles of matter. The relationship between the temperature and the total energy of a system depends on the types, states, and amounts of matter present. (MS‑PS3‑3), (MS‑PS3‑4)

PS3.B: Conservation of Energy and Energy Transfer

  • When the kinetic energy of an object changes, there is inevitably some other change in energy at the same time. (MS‑PS3‑5)
  • The amount of energy transfer needed to change the temperature of a matter sample by a given amount depends on the nature of the matter, the size of the sample, and the environment. (MS‑PS3‑4)
  • Energy is spontaneously transferred out of hotter regions or objects and into colder ones. (MS‑PS3‑3)

PS4.B: Electromagnetic Radiation

  • When light shines on an object, it is reflected, absorbed, or transmitted through the object, depending on the object’s material and the frequency (color) of the light. (MS‑PS4‑2)

ETS1.A: Defining and Delimiting an Engineering Problem

  • The more precisely a design task’s criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that is likely to limit possible solutions. (secondary to MS‑PS3‑3)

ETS1.B: Developing Possible Solutions

  • A solution needs to be tested and then modified on the basis of the test results in order to improve it. There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of a problem. (secondary to MS‑PS3‑3)

 

*There is a strike through part of the DCI elements that are not developed in this unit. In the OpenSciEd Scope and Sequence, students will develop an understanding of changes in state, particularly as they relate to pressure, in OpenSciEd Unit 6.3, and frequency (color) of light in OpenSciEd Unit 8.4. The placement of this OpenSciEd Unit 6.2 and associated units are shown in the OpenSciEd Scope and Sequence

Focal Science & Engineering Practices
  • Developing & Using Models
  • Planning & Carrying Out Investigations
  • Constructing Explanations & Designing Solutions
  • Engaging in Argument from Evidence
Focal Crosscutting Concepts
  • Systems & System Models
  • Energy & Matter
  • Structure & Function
Unit Information
What are prerequisite math concepts necessary for the unit?

Beginning in Lesson 4 and throughout the unit, students focus on pooling and then averaging test results and building an understanding of temperature as a measure of average particle movement. They take measurements in the tenth or hundredth in decimal points, and must consider negative and positive numbers as they mass systems. Prerequisite math concepts that may be helpful include:

  • CCSS.Math.Content.5.NBT.A.3 Read, write, and compare decimals to thousandths.
  • CCSS.Math.Content.5.NBT.A.4 Use place value understanding to round decimals to any place.
  • CCSS.Math.Content.6.SP.A.3 Recognize that a measure of center for a numerical data set summarizes all of its values with a single number, while a measure of variation describes how its values vary with a single number.
  • CCSS.MATH.CONTENT.6.NS.C.5 Understand that positive and negative numbers are used together to describe quantities having opposite directions or values (e.g., temperature above/below zero, elevation above/below sea level, debits/credits, positive/negative electric charge); use positive and negative numbers to represent quantities in real-world contexts, explaining the meaning of 0 in each situation.

 

Calculating a mean of a data set is a target idea in 6th-grade CCMS. Prior to Lesson 4 in this unit, talk to your grade’s math teacher to find out when students will learn how to calculate the mean of a numerical data set in math class this year. If they have worked on this already, ask the math teacher for an example data set they worked with and any suggested modification to your anchor chart for calculating a mean. If students haven’t yet worked through any examples in their math classes, then the pooled temperature data in this lesson will be an example you save to refer to in future lessons in concert with this anchor chart. Also ask the math teacher if students have worked with using negative numbers to represent quantities in the real world. This will inform your decision about how to represent temperature changes in the pooled class data table.

What modifications will I need to make if this unit is taught out of sequence?

This is the second unit in 6th grade in the OpenSciEd Middle School Scope and Sequence. Given this placement, several modifications would need to be made if teaching this unit earlier or later in the middle school curriculum. These include:

  • If taught before OpenSciEd Unit 6.1, supplemental teaching of light interactions with matter, such as reflection and transmission, would need to be added. These ideas are fundamental to the model students need to build of energy transfer through particle collisions.
  • If taught before OpenSciEd Unit 6.1 or at the start of the school year, supplemental teaching of classroom norms, setting up the Driving Question Board, and asking open-ended and testable questions would need to be added. (These supports are built into 6.1.)
  • If taught later in the OpenSciEd sequence after other engineering design challenges, modify the cup design challenge so that students are more involved in defining the problem and determining the criteria and constraints. Currently, Unit 6.2 is students’ first introduction to engineering design in the OpenSciEd 6–8th grade sequence. Therefore it is more scaffolded than it would need to be if the unit were taught much later in the middle school curriculum.
Unit Acknowledgements
Unit Development Team
  • Lindsey Mohan, Unit Lead, BSCS Science Learning
  • Zoe Buck Bracey, Writer, BSCS Science Learning
  • Emily Harris, Writer, BSCS Science Learning
  • Ari Jamshidi, Writer, Stanford University
  • Abe Lo, Writer, BSCS Science Learning
  • Michael Novak, Writer & Reviewer, Northwestern University
  • Tracey Ramirez, Writer, Charles A. Center at UT-Austin
  • Dawn Novak, Pilot teacher, Maple School 
  • Tyler Scaletta, Pilot teacher, North Shore Country Day School
  • Katie Van Horne, Assessment Specialist
  • David Fortus, Unit Advisory Chair, Weizmann Institute of Science
Production Team

BSCS Science Learning

  • Kate Herman, Copyeditor, Independent Contractor
  • Stacey Luce, Editorial Production Lead
  • Valerie Maltese, Marketing Specialist & Project Coordinator
  • Alyssa Markle, Project Coordinator
  • Chris Moraine, Multimedia Graphic Designer
Unit External Evaluation
NextGenScience’s Science Peer Review Panel

An integral component of OpenSciEd’s development process is external validation of alignment to the Next Generation Science Standards by NextGenScience’s Science Peer Review Panel using the EQuIP Rubric for Science. We are proud that this unit has earned the highest score available and has been awarded the NGSS Design Badge. You can find additional information about the EQuIP rubric and the peer review process at the nextgenscience.org website.