Students make, test, and evaluate biodegradable films and gels. They use their knowledge to design devices that release a dye in a controlled manner as they degrade.

By incorporating everyday materials into science lessons, the Materials World Modules (MWM) program at Northwestern University has found the solution to getting students excited about learning science while helping teachers meet national and state education standards.

The modules are easy to organize and inexpensive to run. They can be incorporated into any science class because of the breadth of subjects covered in the Activity and Design Project sections. Each module is a supplemental science unit that takes 1-3 weeks of class time (approximately 10 hours) to complete.

MWM will give students an opportunity to understand the world around them in a way they have never experienced before. The modules promote an awareness of the roles science and technology play in society and guide students to take increased control of their work.

» Module At-a-Glance
» Connecting to Your Curriculum
» Video Clips

Activity 1: Comparing Packing Materials
Students discover that a biodegradable packing material can be as effective as a nonbiodegradable packing material in protecting an egg from breaking.

Activity 2: Hunting for Biodegradable Objects
By searching for common biodegradable objects, students gain an understanding of how biodegradable materials can be used. They draw conclusions about the availability of biodegradable materials today and in the future.

Activity 3: Processing Biodegradable Materials and Comparing Their Mechanical Properties
Students process gelatin, a biodegradable material, into a gel and into two films that vary in density. They discover how these materials vary in strength and compressibility.

Activity 4: Measuring the Degradation Rates of Biodegradable Materials
Environmental conditions can affect the rate at which a biodegradable material breaks down. Students test the effect of pH and temperature on the degradation rates of the gel, films, and other materials they worked with in the previous Activity.

Activity 5: Researching Biodegradable Materials
Students research and write a formal report about a biodegradable material of their choice. The report is to include how the material was developed, how it degrades, and how it is used. From their findings, students should gain an understanding of the close connections among science, technology, and society.

Design Project 1: Designing a Medicine-Delivery Device
Students use what they learned about the processing and degradation of biodegradable materials to develop a model of a medicine-delivery device, which they enter in a contest. Students use gelatin to make the device, and a dye is used in place of medicine. During the contest, students' devices will be tested in a warm acid solution, which simulates conditions in the human stomach.

Design Project 2: Designing a New Biodegradable Product
Based on what they learned about the properties of gelatin, students will propose how gelatin can be used to make a new product or improve an existing one. They will make, test, and evaluate gelatin samples to determine whether the product they proposed is feasible.

Extension Activity 1: Effect of Molecular Weight on Polymers
By observing the movement of a ball bearing through three kinds of liquids, students infer the effect of molecular weight on viscosity. They then apply what they have learned to explain how a liquid polymer can be changed into a solid.

Extension Activity 2: Comparing the Strengths of Gelatin Films
Students investigate how the mechanical strength of a film is related to the concentration of the polymer used to make the film. They make different concentrations of gelatin films and test their breaking strength using a ball-on-ring apparatus.

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Materials World Modules are designed to be easily incorporated into any middle school science or high school science lab or lecture course. The chart below lists the subjects covered in the Activity and Design Project sections of this module.

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Sharon McCoy talks about the Biodegradable Materials Module
Real Player:  low | mid | hi  QuickTime:  low | mid | hi Short clip (about 30 seconds)	Real Player:  low | mid | hi  QuickTime:  low | mid | hi Full length (5 min 12 sec)

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