Unit Overview

Students investigate balanced and unbalanced forces with a focus on friction as they engineer an affordable, eco-friendly slipper with a safe amount of traction. 

  • Grades 6-8
  • Setting: In school
  • Science connection: Balanced and Unbalanced Forces
  • 9 lessons
  • 45 minutes per lesson

Standards alignment

We’ve developed each YES unit with careful attention to NGSS standards. YES units are also designed to integrate with the most popular elementary and middle school curricula. View Standards Alignment

Unit Map

Students are introduced to engineering by designing a phone stand to solve an everyday problem.
Students learn that the disposal of shoes harms the environment and consider why synthetic materials are commonly used in shoes.
Students focus on the outsole as they investigate why traction is important and which outsole materials provide a safe amount of grip.

Students measure the relative force of friction between the outsole materials and flooring and use this data to determine what is safe.

Students brainstorm designs and consider tradeoffs between safe traction, eco-friendly materials, comfort, and cost.

Teams work together to plan and create their first slipper design.
Teams consider the role of failure in engineering as they test and evaluate their first slipper designs.
Students work in teams to plan, create, and test a slipper iteration, using the Engineering Design Process as a guide.
Students share their designs with their peers, discuss the impact their designs may have, and reflect on their engineering work.

Teacher Preparation Videos

Model Phone


Traction Test Station Part 1

Traction Test Station Part 2

Videos for Students

The Problem

Using Data for Design Decisions

Traction Test Procedure

Making a Slipper

Computer Science Modules

User Reviews Analysis

Students use a simple machine learning algorithm to analyze qualitative data collected from slipper users. This module uses free MATLAB interactives from MathWorks.

  • 2 lessons
  • 45 min each

Step Counters

Students develop, test, and iterate a step counting algorithm to evaluate the durability of their slippers. This module uses BBC micro:bits.

  • 3 lessons
  • 45 min each

Our funders

Major support for this project has been provided by MathWorks.

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What’s Included?

  • Teacher Guide (PDF)
  • Teacher Slides (Google Slides)
  • Student Engineering Notebook (PDF or Google Slides)
  • Print Materials (PDF)
  • 2 Computer Science Modules