Technology and the Diversity of Limits

Chapter 3, “Testing Your Way to a Solution,” helps students understand testing. Although they did some testing of products in Chapter 1, “Consumer Concerns,” this chapter helps them focus on why testing is important and how they should conduct fair tests. They will work for a fictitious company to test both boats and rockets and to help the company come up with a rocket design.

In the Engage activity, Propelling You Forward, students will read a scenario and decide whether they think the tests that were done were fair tests. They will share their current understanding about fair tests.

In the Explore activity, Sails, Propellers, and Fuel, teams of students will test one way of moving a boat forward. They will focus on the collection of data and the importance of testing parts of a final design, but they will not yet learn about fair tests.

During the Explain activity, To Be Fair ..., we introduce students to the president of a fictitious company who would like their help selecting a new product line based on reliable results and fair tests. They will learn what fair test means as well as the variables that are important in testing. They will also return to the Explore activity to determine what they would have needed to do to make their test a fair one. Because of the students’ good work for the company during the Explain activity, the president would like them to continue working for him.

In the Elaborate activity, Rocketing to the Top, students will use an interactive simulation to test several parts of a rocket to determine which combination leads to the rocket that will fly the highest and the straightest. They will think about the advantages and disadvantages of using simulations as well as how the testing of parts can help lead to a better final design.

Finally, in the Evaluate activity, Designing the Fuel, students will build rockets according to the tests they ran during the simulation in the Elaborate activity. They then will continue the rocket design by using fair tests to determine the proper combination of ingredients needed for the rocket fuel.

Because of the students’ good work for the company during the Explain activity, the president would like them to continue working for him. In the Elaborate activity, Rocketing to the Top, students will use an interactive simulation to test several parts of a rocket to determine which combination leads to the rocket that will fly the highest and the straightest. They will think about the advantages and disadvantages of using simulations as well as how the testing of parts can help lead to a better final design. Finally, in the Evaluate activity, Designing the Fuel, students will build rockets according to the tests they ran during the simulation in the Elaborate activity. They then will continue the rocket design by using fair tests to determine the proper combination of ingredients needed for the rocket fuel.

Before beginning this chapter, students should have completed the “Doing Technology” chapter as well as Chapter 1 “Consumer Concerns” and Chapter 2 “Diversity in Technology” of this module, Technology and the Diversity of Limits. It would be helpful if they had some knowledge about data tables; however, you can provide that information during the activities if necessary. Students should also have basic computer skills, as they will be using an interactive computer simulation during the Elaborate activity.

Students may harbor misconceptions about the material they will be studying in this chapter. We list some of these misconceptions in this section. Do not take time to go through them as a list of lecture topics for your students, but rather use them to inform your teaching as the conceptions emerge. Many activities included in this chapter work to expose misconceptions and help students develop better mental models:

• Personal experiences can always serve as evidence. Many students, particularly in middle school, think that personal experiences they have had or have heard about secondhand can be considered evidence to support an idea or a hypothesis. Although personal experiences may sometimes be used as evidence, they may also be very subjective. Students should realize that information that results from fair testing and experimentation is evidence that can be used to support ideas and theories. Sometimes students continue to present personal experiences in place of evidence from testing and experiments. This seems to occur because the evidence is in conflict with their beliefs. You should make an effort to emphasize the importance of using evidence from tests to support claims.

• The point of testing is to see cause-and-effect relationships. In science, it is often the case that testing helps scientists determine the relationship between items. In engineering, the point of testing is to produce the best possible outcome. Testing helps engineers maximize their results to create a reliable design for their products. Often this engineering way of thinking is easier for middle school students to understand than the scientific reasons for conducting testing. Students should understand that experimentation is guided by particular ideas and that doing an experiment is a way to test the ideas.

• Conducting an experiment one time provides enough information about an idea. Students often think that if they see something one time in an experiment, then it is the “right” answer. They should realize that repeating an experiment provides more evidence to prove a particular idea. The more times an experiment is conducted, the more confident the experimenter will be that he or she is obtaining reliable results. Of course, the number of times an experiment is repeated must be tempered by the amount of time and money it takes to conduct the experiment. Students should be aware that one sample is not sufficient.

• Simulations are a perfect model for real-world testing. Models are often used in science and technology classes to help students understand difficult concepts. Simulations using computers are an effective way for students to model concepts. However, a great deal of emphasis is often placed on the idea of models as a way of “seeing” a concept. Less emphasis is placed on the disadvantages of using a model or the limitations of a model. Students should think about both the strengths and the limitations of any model they use to represent phenomena.

The Explore activity is more material intensive than many other chapters. You may need some time to collect the materials needed for this activity.

For the Elaborate activity, you will likely need access to computers for two class periods. Be sure to reserve computers or a computer lab in advance of this activity.

The Evaluate activity may also require some time to collect materials. In particular, each team of students will need a pill bottle with a snap cap. Film canisters can also be used, although the pill bottles are better. You can find these online by searching for snap cap pill bottles or snap cap vials. Alternatively, your local pharmacy may be able to provide these items.

The Materials and Advance Preparation sections provide more information about how to prepare for each activity.