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Early in my career, I noticed sporadic attempts to incorporate the field of engineering into high school science classes. In those times, the term “engineering” sounded very intimidating and complicated to me, and I generally stayed in my own comfort zone when planning activities for student learning.

In recent years though, as STEM and Next Generation Science Standards (NGSS) have become more mainstream, I’ve grown more curious about how engineering and chemistry might interconnect.

During a conference I attended, I was inspired by the interesting ways that other teachers were blending engineering concepts into their science classes. So after receiving a lot of encouragement from colleagues, I worked to incorporate “engineering challenges” into my chemistry classroom.

Channeling students’ natural competitiveness

I have always encouraged students to challenge one another during laboratory activities—to see who can measure most precisely, collect the most accurate data, or perform laboratory techniques with the greatest skill. These friendly competitions help students pay closer attention to detail and develop a stronger understanding of the importance of precision and accuracy in science.

By incorporating engineering challenges, I have found a new way to channel students' competitive spirit into meaningful learning experiences. These challenges encourage students to not only apply chemistry concepts but to think critically and work collaboratively, resulting in greater engagement and a deeper understanding of the material.

Many chemistry teachers are unfamiliar with engineering and have doubts about its usefulness in a chemistry classroom. I can attest that the benefits of engineering challenges extend beyond gaining content knowledge.

Students develop communication skills as they present their designs and defend their decisions. They strengthen teamwork and collaboration skills as they work in groups to decide upon and carry out their ideas in the “best” way.

Most importantly, students learn resilience. Rarely does a design work perfectly on the first attempt. They experience firsthand that failure is not the end of the process but rather an opportunity to gather information, make improvements, and to try again.

The basis of any successful engineering challenge in the science classroom includes the following basic steps:

1. The instructor clearly identifies the problem to be solved (The Challenge).
2. The instructor provides the rules of the challenge. This involves establishing criteria (The Requirements) and constraints (The Limitations).
3. Students develop and test ideas. Most ideas will not work perfectly the first time. Students are taught that failure is an important part of this process.
4. Students gather data on what failed and why so that they can redesign their plans to improve results. Allowing for iterative cycles is the step where most teachers will have a difficult time. Not only does repeating test ideas take up time, but the teacher must give up some control and let the students experience failure so they can learn and succeed. With planning and practice, this step becomes easier.

In my classes, I strive to incorporate three to four engineering design challenges throughout a given school year, in addition to other traditional laboratory activities. While these challenges require more class time than a typical lab, I have found the results to be worth that extra investment.

Assessing engineering challenges is like assessing labs

For each challenge, students submit a lab report that documents both their engineering process and their understanding of the underlying chemistry concepts. The report includes:

1. Description of the challenge in the student's own words
2. Labeled sketch or drawing of their initial design
3. Explanation of any design modifications made during testing
4. Results of the challenge, supported by data and observations
5. “Evidence of Understanding” section, in which students explain the chemistry concepts that guided their design decisions.

I typically assess students based on two components: (1) their active participation throughout the engineering challenge and (2) their completed lab report.

These challenges engage students in all three dimensions of the NGSS by requiring them to apply scientific knowledge while solving an authentic engineering problem.

What a challenge looks like

Below are a few examples of engineering challenges, followed by the associated NGSS Performance Expectations each can address, that I use for my regular level chemistry class. These activities can easily be modified for other levels.

Although these activities are presented as engineering design challenges, students must still follow all standard science laboratory safety rules throughout the investigation. Teachers can minimize potential hazards by informally questioning students throughout the design process about reasons and safety considerations for their selected materials, procedures, and testing methods.

Example 1: Chemical-Reaction-Powered Vehicle Challenge (HS-PS1-5 and HS-ETS1-3)

The Challenge: Students will design, construct, and optimize a chemical-reaction-powered vehicle using the reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid).

I typically do this activity in the beginning of the unit on chemical reactions. Prior to this activity, students should understand what a chemical reaction is and how to balance a chemical equation.

Through this challenge, students may investigate factors that affect the reaction rate by changing variables such as concentration of vinegar or mass/moles of baking soda. They can analyze how changing the concentration of vinegar (or the amount of baking soda) affects the distance traveled.

Rules

Criteria:

• Vehicle must travel a minimum distance.
• Vehicle must travel in a straight path.
• Vehicle must be constructed using only the provided materials (e.g., plastic water bottle with cap, wheels, straws, and axles).

Constraints:

• Maximum volume of vinegar allowed
• Maximum mass of baking soda allowed
• Specific dimensions for the vehicle
• Limited construction and testing time (e.g., 40 minutes)
• Limited construction materials (e.g., glue, tape, tissue paper, etc.)

Evidence of Student Understanding

To demonstrate understanding, students must be able to:

• Write and balance the chemical equation for the reaction.
• Identify the reactants and products.
• Explain the science behind the vehicle's motion (i.e., describe how the chemical reaction between baking soda and vinegar produces carbon dioxide gas, creating pressure that propels the vehicle).
• Justify design decisions by explaining how specific modifications affected the vehicle's performance.
• Summarize what was done during the challenge using scientific vocabulary, including terms such as chemical reaction, reactants, products, carbon dioxide, gas pressure, variables, criteria, and constraints.

Example 2: Fireworks and the Flame Test Challenge (HS-PS1-1, HS-PS4-1 and HS-ETS1-3)

The Challenge: Students will create a display of flames with specific color combinations and stay within a specific budget.

I typically do this activity in the middle of the electrons unit. Prior to this activity, students should understand that atoms contain electrons arranged in energy levels, that electrons can gain or lose energy, and that as they do so, they can move between energy levels.

Through this challenge, students may investigate factors that affect the flame color by changing the type of chloride salt put in the flame. They can analyze how changing the chemical can produce a variety of colors.

As a result of this activity, students will develop a deeper understanding of electron transitions and emission spectra. Following the challenge, students learn (1) how excited electrons emit specific wavelengths of light as they return to lower energy levels and (2) how this principle is used to identify elements.

Rules

Criteria:

• Include all requested colors. Each group can be assigned different sets, as in the numbered examples below:
• #1: red, white, and blue
• #2: red, orange, and yellow
• #3: green, blue, and purple (created by combining two colors)
• Produce colors for the longest amount of time

Constraints may include:

• Staying within the budget
• Using only the available chloride salts, water, and wooden splints
• Limited class time

Evidence of Student Understanding

To demonstrate understanding, students must be able to:

• Identify unknown metal ions using observations from flame tests and evidence collected during the investigation.
• Apply engineering design principles by selecting, testing, and refining combinations of chloride salts that satisfy the challenge criteria while working within budget and time constraints.
• Analyze and interpret data by comparing flame colors, brightness, and cost effectiveness to determine the optimal solution.
• Justify design decisions using evidence from their observations to explain why particular salts or combinations of salts were chosen.
• Summarize what was done during the challenge using scientific vocabulary, including terms such as electron excitation, energy levels, emission spectrum, wavelength, photon, metal ion, variables, criteria, and constraints.

Example 3: Electroplating Design Challenge (HS-PS3-3 and HS-ETS1-3)

The Challenge: Design the most effective electroplating system to produce a uniform copper coating. Students are provided with copper sulfate solution, a copper electrode, a power source (battery), and a metal object to be coated.

I typically do this activity towards the end of the redox reactions unit. Prior to this activity, students should understand the basics of a redox reaction, including vocabulary terms such as oxidation, reduction, electrode, anode, and cathode.

Through this challenge, students investigate factors that affect a redox reaction by changing variables such as electrode placement, plating time, and solution concentration. They can analyze how a redox reaction can affect mass, coating thickness, and appearance of an object.

Rules:

Criteria may include:

• Achieve the greatest mass gain.
• Produce the most uniform copper coating.
• Minimize energy usage.
• Minimize plating time.

Constraints may include:

• Fixed voltage
• Limited plating time
• Specific volume of copper sulfate solution
• Restricted electrode sizes

Evidence of Student Understanding

To demonstrate understanding, students must be able to:

• Explain the electrochemical processes occurring during electroplating by describing the oxidation and reduction reactions, the movement of electrons through the external circuit, and the movement of copper ions within the solution.
• Apply engineering design principles by designing, testing, evaluating, and refining an electroplating system that meets the established criteria while working within the given constraints.
• Collect and analyze quantitative and qualitative data by measuring changes in mass, evaluating the uniformity and appearance of the copper coating, and comparing results from multiple trials.
• Use evidence to justify design decisions by explaining how changes in variables such as electrode placement, plating time, or solution concentration affected the quality and efficiency of the electroplating process.
• Summarize what was done during the challenge using scientific vocabulary, including terms such as oxidation, reduction, electrode, anode, cathode, electron transfer, ions, electrolyte, electroplating, variables, criteria, and constraints.

Engineering can bring chemistry into better focus

Chemistry is more than memorizing formulas and balancing equations. It’s about understanding the world around us and using that knowledge to solve problems. Engineering challenges such as the ones described here provide students with the opportunity to do exactly that, turning them from passive learners into active innovators and problem solvers.

Whether students are building a reaction-powered vehicle, designing an electroplating system, or creating colorful flames, they are doing much more than completing a laboratory exercise. They are identifying problems, developing solutions, analyzing data, evaluating trade-offs, and refining their designs based on evidence. These experiences mirror the work of real scientists and engineers and help students develop the critical thinking, collaboration, and problem-solving skills necessary for success beyond the classroom. By intentionally incorporating engineering design into chemistry instruction, teachers can transform traditional labs into authentic STEM experiences that bring science to life.