Hands-on Activity: Invent a Backscratcher from Everyday Materials

Contributed by: Center for Engineering Education Outreach, Tufts University

Summary

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.
This engineering curriculum meets Next Generation Science Standards (NGSS).

An example of two backscratchers.
Students make their own backscratchers
copyright
Copyright © Wikimedia Commons http://upload.wikimedia.org/wikipedia/commons/e/e3/Backscratchers.jpg

Engineering Connection

When engineers design products, they must make sure that they meet the desired functions, as well as consider other important aspects of the designs for the users. Beyond being functional, in many cases the product must also be easy or comfortable to use, and aesthetically pleasing. Engineers also take into consideration material and labor costs, durability to withstand intended use, and efficient material use in manufacturing.

Learning Objectives

  • How to use creativity and everyday materials to build something useful.
  • How to utilize designs and sketches in creating a product.

More Curriculum Like This

Designing Medical Devices for the Ear

Students are introduced to engineering, specifically to biomedical engineering and the engineering design process, through a short lecture and an associated hands-on activity in which they design their own medical devices for retrieving foreign bodies from the ear canal. Through the lesson, they lea...

Time for Design

Students are introduced to the engineering design process, focusing on the concept of brainstorming design alternatives. They learn that engineering is about designing creative ways to improve existing artifacts, technologies or processes, or developing new inventions that benefit society.

Elementary Lesson
Simple Machines and Modern Day Engineering Analogies

Students apply the mechanical advantages and problem-solving capabilities of six types of simple machines (wedge, wheel and axle, lever, inclined plane, screw, pulley) as they discuss modern structures in the spirit of the engineers and builders of the great pyramids.

Olympic Engineering: Design Process to Create Competition Venues

The Olympics are introduced as the unit theme by describing the engineering required to build grand and complex event centers. Then students are introduced to the techniques of engineering problem solving, specifically brainstorming and the steps of the engineering design process.

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.

  • Ask questions, make observations, and gather information about a situation people want to change to define a simple problem that can be solved through the development of a new or improved object or tool. (Grades K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • 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. (Grades K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • Analyze data from tests of two objects designed to solve the same problem to compare the strengths and weaknesses of how each performs. (Grades K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • Identify and describe the safe and proper use of tools and materials (e.g., glue, scissors, tape, ruler, paper, toothpicks, straws, spools) to construct simple structures. (Grades Pre-K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
  • Describe how human beings use parts of the body as tools (e.g., teeth for cutting, hands for grasping and catching), and compare their use with the ways in which animals use those parts of their bodies. (Grades Pre-K - 2) Details... View more aligned curriculum... Do you agree with this alignment?
Suggest an alignment not listed above

Materials List

  • tape
  • string
  • scrap cardboard
  • paper towel tubes
  • scissors
  • glue
  • any other materials you wish to use; students may also bring supplies from home

Introduction/Motivation

Engineers are constantly using their creativity to find solutions to everyday problems. To solve a problem, you must first recognize that the problem exists. For example, have you ever had a pesky itch on your back that you just could not reach? Typically, when you have an itch on your body, your first reaction is to scratch it with your fingernails. However, this itch is an unreachable itch and no one is around to scratch it for you. What do you do? As an engineer, you use your creativity and the materials around you to come up with different solutions and design a backscratcher. What types of materials would you want to use for the backscratcher and why?

Vocabulary/Definitions

lever: A simple machine that utilizes a ridged bar and a fulcrum (pivot point) to raise or move an object.

sketch: A rough drawing or plan of an idea.

Procedure

Recommended Background Resources

Before the Activity

  • Gather materials.
  • (optional) Build a backscratcher as an example to show the students.
  • Have students bring in any backscratchers they might have at home to show.

With the Students

Class Discussion:

  1. Ask the students: Why is it hard to scratch your back?
  2. Discuss why new products are made and innovations take place. (They solve a problem or fill a need.)
  3. Have students show example backscratchers they brought in from home.
  4. Discuss what a backscratcher is and why it is a useful device or tool.
  5. Talk about formulating an idea and sketching a picture before construction.
  6. Talk about what makes a good sketch. Why are plans/sketches an important step in the design process?
  7. Point out how there is more than one way to make a backscratcher. (Bring up different brand names of the same product.)

Activity:

  1. Prepare a station with the materials available for students to use.
  2. Have students work alone or in pairs.
  3. Talk about safety; do not eat the glue, careful with scissors, etc.
  4. Introduce the activity to the students and let them examine the materials, brainstorm for ideas and sketch designs. Have the students explain their sketches to you before they start construction. Tell the students that they may use as much or as little of the materials available.
  5. Once students have completed their backscratchers, have them lay them out on a table so that everyone in the class can see each design. Encourage them to try out the different backscratchers, but remind them to be respectful of everyone's inventions.
  6. 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.

Attachments

Investigating Questions

  • What materials were the best to use for this project?
  • What would you have done differently?
  • What other materials could have worked?
  • What is a good design for a backscratcher?

Assessment

Copyright

© 2013 by Regents of the University of Colorado; original © 2004 Worcester Polytechnic Institute

Supporting Program

Center for Engineering Education Outreach, Tufts University

Last modified: June 11, 2018

Comments