Invent a Backscratcher from Everyday Materials

TeachEngineering Digital Library
Type Category
Instructional Materials
Lesson/Lesson Plan , Model
This resource, vetted by NSTA curators, is provided to teachers along with suggested modifications to make it more in line with the vision of the NGSS. While not considered to be "fully aligned," the resources and expert recommendations provide teachers with concrete examples and expert guidance using the EQuIP rubric to adapted existing resources. Read more here.



Being able to recognize a problem and design a potential solution is the first step in the development of new and useful products. In this activity, students create devices to get "that pesky itch in the center of your back." Once the idea is thought through, students produce design schematics (sketches). They are given a variety of everyday materials and recyclables, from which they prototype their back-scratching devices.  The class will other student's backscratchers and discuss which are the most useful and what they liked about them. Testing them out is a key part of the process. 

Intended Audience

Educator and learner
Educational Level
  • Kindergarten
Access Restrictions

Free access - The right to view and/or download material without financial, registration, or excessive advertising barriers.

Performance Expectations

K-PS2-1 Plan and conduct an investigation to compare the effects of different strengths or different directions of pushes and pulls on the motion of an object

Clarification Statement: Examples of pushes or pulls could include a string attached to an object being pulled, a person pushing an object, a person stopping a rolling ball, and two objects colliding and pushing on each other.

Assessment Boundary: Assessment is limited to different relative strengths or different directions, but not both at the same time. Assessment does not include non-contact pushes or pulls such as those produced by magnets.

This resource appears to be designed to build towards this performance expectation, though the resource developer has not explicitly stated so.

Comments about Including the Performance Expectation
This lesson is being adapted to work with Kindergarten students and the emphasis should be on the engineering aspect as they create their own backscratcher; however it is important to align all engineering projects with a Disciplinary Core Idea. Therefore, this resource can be aligned to motion and stability if the teacher has purposeful conversations with their students regarding push, pull, and different directions strengths.

K-2-ETS1-2 Develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem.

Clarification Statement: none

Assessment Boundary: none

This resource is explicitly designed to build towards this performance expectation.

Comments about Including the Performance Expectation
This lesson is very explicit in discussing how to implement this activity. Discussion questions, student worksheet, and a rubric is provided as well. However, I would suggest that they talk to the students about the shape of their designs and how different shapes work better than others.

Science and Engineering Practices

This resource is explicitly designed to build towards this science and engineering practice.

Comments about Including the Science and Engineering Practice
The class discussion of this lesson includes guiding questions and activities that will help students successfully implement this engineering design project. For example, students are encouraged to bring in backscratchers from home so they will have an example of a backscratcher (building background knowledge for students unfamiliar with backscratchers).

Disciplinary Core Ideas

This resource appears to be designed to build towards this disciplinary core idea, though the resource developer has not explicitly stated so.

Comments about Including the Disciplinary Core Idea
Pushes and pulls can have different strengths and directions. If using strategic and purposeful questioning when students test out each backscratchers the teacher can have a guided discussion on the different strengths and durability of the backscratchers.

This resource is explicitly designed to build towards this disciplinary core idea.

Comments about Including the Disciplinary Core Idea
In step 6 of the activity it states that, "after everyone has tested the designs, have the class decide which of the backscratchers is the most useful and explain what features they liked about it." I think that class discussion is key. I would certainly also ask the students to discuss what they would change about their backscratchers to make improvements based on how they see others’ working (noting that they would be basing changes on evidence). The writers of the lesson claim that it lines up with a standard of having students “analyze data from tests of two objects… to compare the strengths and weaknesses.” I would also go into questions such as, why are some materials better than others? Which materials are best? What’s the same about those materials? If made of cardboard, why does it matter which way you hold the cardboard? (one way it’s more rigid/strong, one way it just bends, it’s weaker).

Crosscutting Concepts

This resource appears to be designed to build towards this crosscutting concept, though the resource developer has not explicitly stated so.

Comments about Including the Crosscutting Concept
Teachers can scaffold students understanding of the Crosscutting Concept by having a discussion on the shape/structure of different backscratchers and whether or not the design has an impact on the function (i.e. to scratch your back.) Teachers will have to model and explain that the effectiveness of each design is based on the overall design of each backscratcher.

Resource Quality

  • Alignment to the Dimensions of the NGSS: It has the potential to get into simple machines and pushes and pulls, as well as comparing different materials and their properties, but it doesn’t go there with the students. Why do you want it to be able to push strongly on your back? Why are some materials better able to “push” on your back than others to give you that good scratch? How does the shape of the design make a difference?

  • Instructional Supports: - none -

  • Monitoring Student Progress: Although a rubric is provided, it is not student friendly. The student worksheet can be adapted and utilized for students to draw and reflect on their progress. The rubric could better emphasize the engineering design process by adding the following elements: Did the student test their design to see if it works and change it to make it better? Or, did the students share ideas with each other and work in a group well? Also, I would have students work in pairs or groups of three – working alone is not getting at engineering capacities well.

  • Quality of Technological Interactivity: There is no technological interactivity with this resource.