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Chemical Reactions & Engineering Design

Classroom Resource Information

Title:

Chemical Reactions & Engineering Design

URL:

https://www.middleschoolchemistry.com/lessonplans/chapter6/lesson11

Content Source:

Other
American Chemical Society

Type:

Lesson/Unit Plan

Overview:

This lesson begins with a story about rescuing reptile eggs from a new construction site. Using the story as motivation, students are presented with an engineering design challenge: Build a portable device that can warm, support, and protect one reptile egg as it is moved from a construction site to a nearby reptile conservation center. After observing different heat packs, students discuss the criteria and constraints related to designing a heat pack as the basis for their device. Students investigate calcium chloride as an exothermic dissolver and then move on to calcium chloride and baking soda as the exothermic chemical reaction which will serve as the heat source for their device.

Students adjust the amounts of the reactants (water, calcium chloride, and baking soda) to achieve the right temperature range and then test a prototype in a sealed zip-closing plastic bag. Students use their findings and ideas about insulation and heat transfer to draw an optimized design that 1) Keeps an egg at the ideal temperature, 2) Holds an egg in the proper orientation, and 3) Protects the egg from impact. Each student or student group draws this device and explains how the device meets each of the three criteria.

Content Standard(s):

Science
SC2015 (2015)
Grade: 8
Physical Science

7 ) Design, construct, and test a device (e.g., glow stick, hand warmer, hot or cold pack, thermal wrap) that either releases or absorbs thermal energy by chemical reactions (e.g., dissolving ammonium chloride or calcium chloride in water) and modify the device as needed based on criteria (e.g., amount/concentration, time, temperature).*

Unpacked Content

Scientific And Engineering Practices:

Constructing Explanations and Designing Solutions

Crosscutting Concepts: Energy and Matter

Disciplinary Core Idea: Matter and Its Interactions

Evidence Of Student Attainment:

Students:

Design a device that either releases or absorbs thermal energy by chemical reactions.
Construct a device that either releases or absorbs thermal energy by chemical reactions.
Test a device that either releases or absorbs thermal energy by chemical reactions.
Modify the device as needed based on criteria.

Teacher Vocabulary:

Design
Construct
Test
Modify
Device (e.g., glow stick, hand warmer, hot or cold pack, thermal wrap)
Engineering
Engineering Design
Process
Temperature
Exothermic (release thermal energy)
Endothermic (absorb thermal energy
Thermal energy
Chemical reactions (e.g., dissolving calcium chloride in water)
Criteria (e.g., amount/concentration, time, temperature)

Knowledge:

Students know:

Engineering is a systematic and often iterative approach to designing objects, processes, and systems to meet human needs and wants.
The Engineering Design Process (EDP) is a series of steps engineers use to guide them as they solve problems.
The EDP may include the following cyclical steps: ask, imagine, plan, create, and improve.
In chemical reactions, the atoms that make up the original substances are regrouped into new substances with different properties.
Chemical reactions can release thermal energy or store thermal energy. Criteria are requirements for successful designs.

Skills:

Students are able to:

Design and construct a solution to a problem that requires either heating or cooling.
Describe the given criteria and constraints.
Test the solution for its ability to solve the problem via the release or absorption of thermal energy to or from the system.
Use the results of the tests to systematically determine how well the design solution meets the criteria and constraints, and which characteristics of the design solution performed the best.
Modify the design of the device based on the results of iterative testing, and improve the design relative to the criteria and constraints.

Understanding:

Students understand that:

Some chemical reactions release energy, others store energy.
The transfer of energy can be measured as energy flows through a designed or natural system.
A solution needs to be tested, and then modified on the basis of the test results, in order to improve it.
Although one design may not perform the best across all tests, identifying the characteristics of the design that performed the best in each test can provide useful information for the redesign process - that is, some of the characteristics may be incorporated into the new design.
The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution.

AMSTI Resources:

AMSTI Module:
Experimenting with Mixtures, Compounds, and Elements

Alabama Alternate Achievement Standards

AAS Standard:
SCI.AAS.8.7- Critique objects or materials used to minimize or maximize thermal energy transfer (e.g., gloves, insulated hot pad, foam cup).

Tags:

baking soda, calcium chloride, chemical reaction, heat pack, temperature, thermal energy

License Type:

Custom Permission Type
See Terms: https://www.acs.org/content/acs/en/terms.html
For full descriptions of license types and a guide to usage, visit :
https://creativecommons.org/licenses

Accessibility

Comments

This resource provided by:

Author:

Stephanie Carver

ALEX Classroom Resource

Chemical Reactions & Engineering Design