Jess Makes Hair Gel provides an account of a boy who sets out to make his own hair gel.
In the book, Jess identifies the properties of a good hair gel and then tests different ingredients to see which have these properties. While conducting tests on each ingredient, Jess realizes that he needs to expand the list of properties of good hair gel to include several more. With this realization he is able to solve problems he encounters and end up with a great hair gel.
This book models the steps of the design process that students use in the unit.