Hands-on Activity Engineering in Reverse!

Quick Look

Grade Level: 6 (6-8)

Time Required: 1 hours 15 minutes

Expendable Cost/Group: US $0.00

(Note: Screwdrivers and push-toys are reusable. Push-toys can be purchased for $US ~$7-10 each at most toy stores or http://tomy.com/push-n-go-truck. Screwdrivers can be purchased for less than $US 1 at most bulk hardware stores.)

Group Size: 3

Activity Dependency: None

Subject Areas: Science and Technology

NGSS Performance Expectations:

NGSS Three Dimensional Triangle


Students learn about the process of reverse engineering and how this technique is used to improve upon technology. Students analyze push-toys and draw diagrams of the predicted mechanisms inside the toys. Then, they disassemble the toys and draw the actual inner mechanisms. By understanding how the push-toys function, students make suggestions for improvement, such as cost effectiveness, improved functionality, ecological friendliness and any additional functionality they determine is an improvement.
This engineering curriculum aligns to Next Generation Science Standards (NGSS).

Photo shows a bright-colored plastic push-toy, a little train engine.
Figure 1. Push-toys can be reverse engineered to understand how they work and suggest improved designs.
Copyright © 2004 Microsoft Corporation, One Microsoft Way, Redmond, WA 98052-6399 USA. All rights reserved.

Engineering Connection

Engineers learn about technologies, objects and systems through reverse engineering and the engineering design process. By analyzing the structure and function of a device or component, engineers can improve upon previous designs.

Learning Objectives

After this activity, students should be able to:

  • Define reverse engineering as the process of disassembly and careful analysis with the goal of duplicating or improving a device or component.
  • Demonstrate the process of reverse engineering using a given object or component and suggest areas of improvement.

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

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. (Grades 6 - 8)

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This activity focuses on the following Three Dimensional Learning aspects of NGSS:
Science & Engineering Practices Disciplinary Core Ideas Crosscutting Concepts
Develop a model to generate data to test ideas about designed systems, including those representing inputs and outputs.

Alignment agreement:

Models of all kinds are important for testing solutions.

Alignment agreement:

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.

Alignment agreement:

  • Evaluate designs based on criteria, constraints, and standards. (Grades 3 - 5) More Details

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  • Design involves a set of steps, which can be performed in different sequences and repeated as needed. (Grades 6 - 8) More Details

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  • Make two-dimensional and three-dimensional representations of the designed solution. (Grades 6 - 8) More Details

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Materials List

Each group needs:

  • 2-3 copies of the Engineering in Reverse Worksheet (pdf), one per student
  • 1 push-toy (available at most toy stores, such as at Target®)
  • 1 small Phillips-head screwdriver (borrowed from other school classrooms or purchased at Lowe's® or Home Depot® for less than $US 1 each)
  • 1 small bowl or bin for screws and small pieces

Worksheets and Attachments

Visit [www.teachengineering.org/activities/view/cub_engineering_in_reverse] to print or download.

Pre-Req Knowledge

Students should understand that engineers use the engineering design process (see Background information under the Procedures section) to invent and improve technologies, objects and systems. In this activity, students focus on the "asking and improving" steps in the engineering design process.


By studying an existing engineered object, we can learn a lot about how the object was designed and how it works. What steps might an engineer take to figure out and understand how an existing product works? Usually, we can just take it apart! Engineers use a process called reverse engineering to understand how something functions and to determine ways it can be improved. Have you ever taken something apart to find out what is inside? If you have, then you have already "reverse engineered!"

By carefully discovering how something was made and how it works, engineers can make suggestions for areas of improvement of the product. Sometimes the improvement is very simple. For example, suppose you reverse engineered a computer hard drive and noticed that one of the screws is not necessary. This may seem like a small detail, but if that screw costs five cents and it is removed from 1 million computer hard drives manufactured in one year, that saves $50,000! Imagine if you found two screws that were not necessary! A few small changes can make a big difference.

Reverse engineering, however, is not simply taking something apart. This process requires careful observation, disassembly, documentation, analysis, and reporting. Many times, the reverse engineering process is non-destructive. This means that the object or component can be reassembled and still function just as it did before you took it apart.

Today, we will practice reverse engineering using children's push-toys. Before we take them apart, we will test the toys and record our predictions of how they work. We will each draw what we think is inside the toys making them work. It is perfectly acceptable to be unsure of a toy's internal "parts" — just make your best prediction. When everyone is done with their first drawing, we will carefully disassemble the toys and make notes about the process so we can reassemble them. Throughout the reverse engineering project, we will think of ways these objects could be improved. Is there some way it could function better? Or be manufactured less expensively? We will use our observations to make suggestions for improvement to the toys.



Engineers use the engineering design process to invent and improve technologies, objects and systems.

The engineering design process includes five critical steps:

  1. Ask – What is the problem? What have others done?
  2. Research -- What aready exists? Talk to people with different backgrounds!
  3. Imagine – What is the best solution? Brainstorm ideas.
  4. Plan – Draw a diagram. List the materials you need.
  5. Create – Follow your plan and build your prototype.
  6. Test -- Does it work? Does it solve the need?
  7. Improve – How can you improve your design? Go back to Step 1.

A flowchart of the engineering design process with seven steps placed in a circle arrangement: ask: identify the need and constraints; research the problem; imagine: develop possible solutions; plan: select a promising solution; create: build a prototype; test and evaluate prototype; improve: redesign as needed, returning back to the first step, "ask: identify the need and constraints."
The steps of the engineering design process.
Copyright © TeachEngineering.org. All rights reserved.

Engineers also use the process of reverse engineering to understand existing technologies, objects, components and systems. By carefully disassembling, observing, testing, analyzing and reporting, engineers can understand how something works and suggest ways it might be improved.

Before the Activity

  • Gather enough push-toys for the class, one for each group of 2-3 students.
  • Make copies of the Engineering in Reverse Worksheet (pdf), one for each student.
  • Explain to students that reverse engineering is the process of carefully taking something apart to understand how it works and suggest possible areas of improvement.
  • Write the definition of reverse engineering on the board

With the Students

  • Divide the class into groups of 2-3 students each and give each group one push-toy.
  • Tell students to spend about five minutes testing the push-toys and discussing within their groups how the toy functions. Encourage students to consider the mechanisms inside the toy.
  • Hand out one worksheet to each student. Explain that the worksheet contains three sides: the first page is completed before disassembling the toy and the rest is completed after disassembly.
  • Students should complete the first page of the worksheet by drawing their predictions of the inner mechanisms of the toy. Allow enough time (about 15-20 minutes) for students to complete detailed drawings.
  • While students are working, ask the following questions to the groups:

- How does the toy work?

- What might be inside the toy to make it work this way?

  • Be sure the students have completed their initial drawings before handing out screwdrivers for disassembly.
  • Allow groups to begin taking apart the push-toys. Remind all groups to be extra careful not to lose any pieces (such as small screws, tiny washers, springs, etc.). Instruct students to immediately place all pieces in a small bowl or bin to keep them safe for the reassembly.
    Three pictures of students in the process of reverse engineering a push-toy. Shown, the students are in various stages of manipulating the toys for study or disassembly.
    Figure 2. Students in the process of reverse engineering a push-toy.
    Copyright © Photographs by Megan Schroeder, University of Colorado at Boulder, ITL Program, 2008.
  • Once the groups are done disassembling their push-toys, have them complete the rest of the worksheet by drawing the actual mechanisms.
  • Be sure to leave enough time for students to reassemble the toys.


diagram: A visual representation of a system, process, technique or individual components that make up a part or product; often is black and white.

reverse engineering: The process of taking something apart to understand how it works and suggest improvements.


Pre-Activity Assessment

Question/Answer: Ask students the following questions and have them raise their hands to answer.

  • As engineers, how do we figure out how something works? For example, suppose we want to know how a toaster works? (Answer: We learn how things work by taking them apart. By doing this, we can figure out what is inside and how it works.)
  • What do you think reverse engineering means? (Answer: Reverse engineering is the process of taking something apart to understand how it works.)
  • Other than learning about how an object functions, what is another goal of reverse engineering? Example? (Answer: Other goals of reverse engineering are to improve the device's function, make it more cost efficient, make it more ecologically friendly, change the function, or create another use for the object. An example: finding out that one of several screws are not necessary for the performance or durability of a particular product, which could save huge manufacturing costs when hundreds or thousands are produced.)

Activity Embedded Assessment

Worksheet: Have students complete the Engineering in Reverse Worksheet and review their answers to determine their level of understanding.

Post-Activity Assessment

Presentation: Have students discuss the following topics within their groups. Then assign one topic to each group and have students present their ideas to the class.

  • Describe how the device was disassembled.(Students may explain where the screws were located and how the inside components were taken apart from each other.)
  • What did you learn about the device's design and function? (Students may explain that the toy is designed to be used by small children, so it is difficult to take apart and is very robust. Also, it contains simple mechanisms that work for a very long time.)
  • Describe the key components and how they function. (For example, the spring turns the gear, which is attached to the wheel axle.)
  • Suggest changes that would improve the device's function. (Students may explain ways to redesign the toy so that the spring does not get stuck, the toy goes faster, etc.)
  • How could the device be more cost effective to produce? (Students may suggest that fewer screws be used, child-safe glue is used instead of screws, or fewer gears be used.)

Troubleshooting Tips

If push-toys are not available, use other objects, such as water toys, audio speakers, coffee makers, combination locks, wind-up toys, toasters, blenders, computer keyboards, Etch-a-Sketch™ toys, etc., which can be obtained from yard sales, toy stores, hardware stores or second-hand stores.

Activity Extensions

  • Have the groups present the mechanisms they reverse-engineered to the entire class. Then, have the groups re-design a toy that uses at least two of the different mechanisms they just learned about.
  • Have students create an advertisement (print, video or audio), marketing the re-engineered push-toy to an identified target audience. Students should describe the purpose of the object and the improvement(s) they have made.

Activity Scaling

  • For lower grades, disassemble one push-toy as a class. This prevents them from getting frustrated from using a screwdriver and losing small parts.
  • For upper grades, have students reassemble the toys to perform different functions. For example, the reassembled toy must go backwards or must turn in one direction. This challenges students to really understand how the mechanisms work.


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Abarca, Javier, et al. Introductory Engineering Design: A Projects-Based Approach. (Textbook for GEEN 1400: First-Year Engineering Projects course.) Third Edition (spiral bound), Eds. Janet L. Yowell and Denise W. Carlson. Boulder, CO: Integrated Teaching and Learning Laboratory, College of Engineering and Applied Science, University of Colorado at Boulder, Fall 2000. http://itll.colorado.edu/index.php/courses_workshops/geen_1400/resources/textbook/

Boston Museum of Science, Engineering is Elementary, "The Engineering Design Process," accessed June 24, 2009. http://www.mos.org/eie/engineering_design.php


© 2009 by Regents of the University of Colorado


Megan Schroeder; Malinda Schaefer Zarske; Janet Yowell

Supporting Program

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


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: May 4, 2022

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