MS-ETS1-2: Competing Design Solutions

MS-ETS1-2
Competing Design Solutions

Middle School

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Learning Objectives

• Define criteria and constraints for evaluating engineering design solutions.

• Use a decision matrix to evaluate competing design solutions.

• Explain how airbags and safety glass meet specific design criteria.

• Analyze how the laws of motion act as a constraint in car safety design.

Key Vocabulary

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Criteria

Criteria are the standards for judging the success of a design solution after it is completed.

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Constraints

Constraints are the limits on a design, such as the available budget, time, and materials.

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Systematic Process

A systematic process is an orderly method of evaluation used for testing different possible design solutions.

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Decision Matrix

A decision matrix is a useful tool that is designed to help you compare different solutions.

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Design Solution

A design solution is a final plan or product that is created to solve a problem.

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Tempered Glass

Tempered glass is a type of safety glass that is designed to shatter into safe pieces.

Key Vocabulary

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Laminated Glass

Laminated glass is a type of safety glass that holds together when shattered, preventing dangerous shards.

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Air Bag

An air bag is a vehicle safety device that quickly inflates to protect passengers during a collision.

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Deceleration

Deceleration is the scientific term for slowing down, or the rate at which an object decreases speed.

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Crash-Test Dummies

Crash-test dummies are human-like models used in vehicle tests to measure the effects of a crash.

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What are Criteria and Constraints?

Criteria

• Criteria are the goals or requirements that a design needs to meet to be successful.

• They act like a checklist to measure if the design has achieved its purpose.

• For a car, criteria include protecting passengers, being affordable, and being reliable.

Constraints

• Constraints are the limitations or challenges you must work within, like rules you must follow.

• These can include the project's budget, the available materials, or the time you have.

• The laws of physics, like the laws of motion, also act as constraints on a design.

Multiple Choice

What is the main purpose of establishing criteria for a design?

• To define the goals and requirements a design must meet to be successful.

• To list the limitations and challenges that must be followed.

• To describe the budget, materials, and time available for a project.

• To explain the scientific laws that will impact the design.

Multiple Choice

How are criteria different from constraints in a design project?

• Criteria are the goals of the project, while constraints are the limitations.

• Criteria are the limitations of the project, while constraints are the goals.

• Criteria focus on the budget, while constraints focus on the materials.

• Criteria and constraints are both types of goals for a design.

Multiple Choice

A company is designing a new car that must be affordable and reliable, but they have a limited budget and must follow the laws of motion. Which statement correctly classifies a constraint and a criterion for this project?

• The limited budget is a constraint, and the need to protect passengers is a criterion.

• The need to protect passengers is a constraint, and the limited budget is a criterion.

• The laws of motion and the project's budget are both criteria.

• The car's reliability and its affordability are both constraints.

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How Do We Evaluate Solutions?

• Engineers use a systematic process to fairly choose the best design solution.

• A decision matrix is a table used to compare different design options.

• The matrix compares designs against the project's criteria and constraints.

• This helps identify strengths and weaknesses to make a data-based decision.

Multiple Choice

What is the primary goal when engineers evaluate multiple design options?

• To select the best solution using a systematic process.

• To build every possible design that is suggested.

• To choose the design that is the most popular.

• To create a list of opinions about each design.

Multiple Choice

What is the function of a decision matrix in helping engineers choose a solution?

• To compare the strengths and weaknesses of each design.

• To provide a final drawing of the chosen design.

• To calculate how much each design will cost to build.

• To allow engineers to vote for their favorite design.

Multiple Choice

An engineering team is choosing between three designs for a new water filter. What is the most critical basis for their final decision?

• The evidence and data showing which design best meets the criteria.

• The personal opinion of the most experienced engineer.

• The design that is the easiest and quickest to build.

• A public survey showing which design people like the most.

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Solution 1: Safety Glass

Tempered Glass

• This type of glass is commonly used for the side and back windows of a car.

• When it breaks, it is designed to shatter into many small, ball-shaped pieces that are not sharp.

• Its main purpose is to prevent passengers from being cut by sharp glass splinters during an accident.

Laminated Glass

• This glass is used for the front windshield of a car and is made of multiple layers.

• It has a strong, clear plastic core placed between two layers of glass, holding them together.

• This feature helps protect passengers from flying glass and other objects during a collision.

Multiple Choice

What is the primary purpose of using safety glass in cars?

• To make the car look more stylish and modern.

• To reduce the overall weight of the car.

• To reduce the risk of injury to passengers during a car accident.

• To make the windows easier to clean.

Multiple Choice

What is the key difference in how tempered glass and laminated glass behave when they break?

• Tempered glass is made of multiple layers, while laminated glass is a single sheet.

• Tempered glass is used for the front windshield, while laminated glass is used for side windows.

• Tempered glass shatters into small, dull pieces, while laminated glass is held together by a plastic layer.

• Tempered glass protects from flying objects, while laminated glass prevents cuts.

Multiple Choice

Based on its features, why is laminated glass the most suitable choice for a car's front windshield?

• It shatters into many small, ball-shaped pieces that are not sharp.

• Its plastic core holds the glass together, preventing objects from flying into the car.

• It is much thicker and heavier than any other type of glass.

• It is less expensive to produce and install than tempered glass.

Solution 2: Air Bags

• Airbags are fabric bags that provide an energy-absorbing surface during a collision.

• It inflates and deflates rapidly, which lengthens the passenger's stopping time.

• Airbags must be used with seat belts for maximum safety and protection.

• Airbags are fabric bags that provide an energy-absorbing surface during a collision.

• It inflates and deflates rapidly, which lengthens the passenger's stopping time.

• Airbags work best when used with seat belts because the seat belt helps keep the passenger in position, allowing the airbag to absorb the impact effectively.

Multiple Choice

What is the main purpose of an airbag?

• To provide an energy-absorbing surface during a collision.

• To replace the need for a seat belt in a car.

• To make the car's interior more comfortable for passengers.

• To cool down the car's cabin during hot weather.

Multiple Choice

How does an airbag's rapid inflation and deflation protect a passenger?

• By creating a rigid barrier against the dashboard.

• By pushing the passenger back into their seat.

• By lengthening the passenger's stopping time.

• By making a loud noise to warn the driver.

Multiple Choice

Based on the information, what is the best explanation for why an airbag must be used with a seat belt for maximum safety?

• The seat belt is needed to keep the passenger in the proper position for the airbag to work safely.

• The airbag will not inflate unless the passenger is wearing a seat belt.

• The seat belt absorbs most of the energy, while the airbag is only for comfort.

• The airbag only protects during front-end collisions, while the seat belt works for all types.

Gathering Evidence: Crash Testing

• Engineers use crash-test dummies with sensors to collect injury data during controlled experiments.

• This data is evidence used to evaluate how well a design protects passengers.

• The goal is to control a passenger's deceleration rate during a crash.

Gathering Evidence: Crash Testing

• Engineers use crash-test dummies with sensors to collect injury data during controlled experiments.

• This data is evidence used to evaluate how well a design protects passengers.

• The goal is to control a passenger's deceleration rate during a crash.

Multiple Choice

What is the main goal for engineers when using crash-test dummies in controlled experiments?

• To control how quickly a passenger slows down during a crash.

• To increase the number of sensors used in an experiment.

• To measure the total force of the car's impact.

• To prevent any damage to the car's exterior.

Multiple Choice

What is the relationship between the injury data collected from crash-test dummies and a car's design?

• It is used as evidence to see how well the design protects passengers.

• It determines the final color and shape of the car.

• It helps engineers decide where to place the sensors on the dummy.

• It measures the speed of the car before the crash happens.

Multiple Choice

If data from a crash-test dummy shows a very high and rapid rate of deceleration, what is the most logical conclusion an engineer can draw?

• The design is likely ineffective at protecting passengers from injury.

• The crash-test dummy's sensors were not working correctly.

• The car needs to be tested at a much higher speed.

• The design has successfully achieved its safety goal.

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Common Misconceptions

Misconception	Correction
Engineering is just about building things.	It's a process of planning, testing, and evaluating solutions.
You don't need a seat belt if your car has airbags.	Airbags are designed to work with seat belts for your safety.
The most dangerous part of a car crash is the car breaking.	A primary danger is your internal organs hitting your skeleton.

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Summary

• Engineers evaluate solutions using a systematic process based on criteria and constraints.

• A decision matrix is a tool used to compare different design solutions.

• Air bags and seat belts must be used together for maximum safety.

• Crash-test dummies provide data to evaluate how well a design protects passengers.

Poll

On a scale of 1-4, how confident are you about evaluating design solutions using criteria and constraints?

• 1

• 2

• 3

• 4