Childrens' Engineering: Scratch My Back

Overview

This lesson is based on the book Big Smelly Bear by Britta Teckentrup. In the book, a big, smelly bear has an itch in the middle of his back and can't scratch it. Nothing the bear tries works. Using the Engineering Design Process, children will design, build, and test a backscratcher for themselves.

The activity, Invent a Backscratcher from Everyday Materials developed by Worcestor Polytechnic Institute, will be used as the basis for this lesson with modifications as shown below.

Objectives

Students will be able to:

Brainstorm several ideas for a backscratcher
Predict which materials will make the best device
Use prior and new knowledge to design the device
Compare the suitability of different designs
Describe in simple terms what an engineer does

Time

One hour for introduction to what engineers do; reading of story; designing, building and testing solution.

Materials

Big Smelly Bear by Britta Teckentrup
Activity: Invent a Backscratcher from Everyday Materials developed by Worcester Polytechnic Institute and available on http://www.teachengineering.com .
Additional material suggestions: pipe cleaners, popsickle sticks, straws, balsa wood, plastic forks & spoons, rubber bands, rulers

Procedure

Introduction

Ask children if anyone wants to be an engineer when they grow up. Ask if anyone knows what an engineer does. Explain that engineers design things to help people. And they figure out how to solve problems.
Read first half of Big Smelly Bear to children. Introduce the problem: The bear has an itch on his back that he can't scratch.

Brainstorm

Stand up and pretend you have an itch in the middle of your back. Try to scratch it.
How could the bear's problem be solved?
What type of device could an engineer design and build that would help the somone scratch his/her back?
How will you know if it works?

Design and Construct

Provide constraints:

Work individually or in small groups of 2
Use only the materials provided
Design and build something to scratch your back

Students work to plan their ideas by sketching design first
Student build their devices

Evaluation of Designs

To test designs, have students swap backscratchers with another student or group and test out on themselves
The backscratchers must reach the middle of their backs, be easy to use and not fall apart
If time allows have the students work on improving their designs

Wrap-up

Re-assemble children and ask a few students to describe their solutions – what worked and what didn't work. What would they do differently next time?
Finish reading Big Smelly Bear to children to see how the bear's problem was solved.

Photo Examples

Implementation in a Kindergarten class. Click for larger view.