Students learn how the components of concrete can be modified to alter the properties of concrete. They use their knowledge to make concrete roofing tiles that meet specific design and performance criteria.

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
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Activity 1: Hunting for Objects Made of Concrete
By identifying concrete objects in their surroundings, students recognize the widespread use of concrete as an infrastructure material. From their observations, students deduce reasons why concrete is the most common infrastructure material used today.

Activity 2: Comparing Different Kinds of Cements
Students observe changes that occur as cement hardens and conclude that the cement-hardening process involves chemical and physical changes. Students also explore the effects of additives on cement.

Activity 3: Comparing Different Concrete Formulations
Students make concrete samples using different formulations. They discover that the density of concrete can be changed by changing the proportions of its components-coarse aggregate, fine aggregate, cement, and water.

Activity 4: Testing Properties of Concrete
Using the samples they made in the previous Activity, students observe how the proportions of the components of concrete affect its strength and brittleness.

Activity 5: Reinforcing Concrete
Students test the effects of three types of reinforcing materials-metal bars, screens, and fiber pieces-on the strength and brittleness of concrete. They draw conclusions about the way each type of reinforcement improves the properties of concrete.

Design Project 1: Designing a Concrete Roofing Tile
Using what they learned about concrete from the Activities, students design and test prototypes of a concrete roofing tile. To be considered successful, the prototypes must meet specific design and performance criteria.

Design Project 2: Designing a New Concrete Product
Possible uses of concrete are explored in this Design Project. Students design and test prototypes of a new concrete product of their choice and, based on their data, draw conclusions about the feasibility of their proposed product.

Extension Activity 1:Chemical Degradation in Concrete
In Part A, students compare the porosity of various concrete formulations by measuring the formulations' electrical resistance. In Part B, students explore the effect of the water-to-cement ratio on the chemical degradation of concrete by acid. They use data from Part A to explain their results and to describe the mechanism by which chemicals degrade concrete.

Extension Activity 2: Making "Flexible" Concrete
Students use layers of fiberglass to make concrete that appears to be flexible. They become more appreciative of the versatility of concrete as an infrastructure material when they see a flexible concrete that bends and stretches easily when a load is placed on it.

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Materials World Modules are simple to organize and inexpensive to run. They 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 Activities and Design Projects sections of this module.

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Fiber-reinforced Concrete
Describes how fiber is used to reinforce concrete. Includes its theory, properties, and uses.

Portland Cement Association
Furnishes information about cement and concrete for a wide variety of infrastructure needs.

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