Iowa Alumni Magazine | April 2008 | Feature

Inventions for Middle Schoolers

By Melissa Rooney & Hauscin Deborah L.
Children learn that people have invented machines that enable fun, as well as ease work.

photo of ferris wheel

The unit focused on the theme of Invention, which referred to both inventive thought and the products created through invention. In addition to the text series adopted by my district, the resources I used in this unit included a set of nonfiction books that engaged students in all areas of inventions, inventors and machines. I found the following books to be useful in my teaching, highly interesting to my students, and well suited to the diverse reading abilities in my classroom: The New Way Things Work; Eyewitness Books; Invention; So You Want to Be an Inventor; What a Great Idea: Inventions that Changed the World; and Accidents May Happen: Fifty Inventions Discovered by Mistake. The approach I used reflects the greater emphasis on learning subject matter disciplines in the context of technology, and the history and nature of science, rather than studying subject matter disciplines for their own sake.

. . . We began our investigation of science and technology from a historical angle, with students conducting an in-depth inquiry into individuals they considered "inventors." Students developed research projects that revolved around their own interests and questions concerning the inventions and inventors they selected.

Students' investigations spanned a broad spectrum, ranging from Marie Curie and Thomas Edison to more contemporary creators of inventions, including the Rubik's Cube, Gatorade, and Post-It notes. The choices made by peers triggered a discussion of the relative value of particular inventions to society in comparison to others. For example, a student who selected Marie Curie (someone who, in her mind, made significant contributions to society) questioned her classmate's choice to investigate the inventor of Gatorade. This debate highlighted the ways in which "social needs and values influence the direction of technological development" (NRC 1996, p. 169) as well as the diverse social and personal perspectives held by different individuals.

. . . Students . . . [examined] how their inventor was inspired by, and in turn, affected society. To share the products of their research, students created posters and presented them to their classmates in an open forum. This public communication of student ideas and work to classmates reflects the shift in emphasis away from private communication of student work to the teacher alone. . . .

The second phase of the unit engaged students in the process of inquiry. . . . I wanted students to enhance their knowledge and understanding of simple machines by allowing them to study fundamental concepts by conducting in-depth investigations of each machine over an extended period of time. . . . One of the most beneficial aspects of the inquiry approaches I learned through my professional development has been the realization that devoting an extended period of time to these investigations is necessary to allow students to develop their interests in a particular topic. Before, I would have thought that students would have grown bored or been ready to move on to the next thing, but what I found was that the longer that we were involved in the unit, the more I felt students became engaged in the topic. I really felt they began to develop the big picture in respect to connections among the concepts, as well as applications to their daily lives. The following sections describe the investigations that students participated in for each simple machine studied.

In the initial design of the unit, I envisioned presenting students with a guided inquiry, or question concerning a particular simple machine, in addition to appropriate materials for them to explore and investigate. I did not give students a set of directions for following a particular method. As I had anticipated, I observed that students developed their own ideas of how to explore and investigate each machine. While they worked, I was available to guide students with questions such as "What would happen if you moved the fulcrum?" or "How does the way in which you arrange the pulleys influenced the amount of effort you need to exert?" and provide additional materials they required.

Levers

During the first investigation, students explored the three different classes of levers, focusing on the concepts of effort, fulcrum, and load. Students were given yardsticks (levers), clay and film canisters (fulcrums), and washers (loads) to begin their investigations. (Their own effort was used to raise the load.) I wanted students to recognize the connection between the placement of the fulcrum, and the amount of effort needed in relationshipo to the load. As a teacher, it was interesting to stand back and watch as students explored these very basic materials; each had his or her own way of approaching the investigation. Some were concerned immediately wlith balance and the placement of the load, while others focused more on the placement of the fulcrum.

After they had sufficient time to explore, we came together as a large group to discuss what the students had observed. This type of discussion, involving students diagramming different levers on the board, provided a place for them to share their ideas, observations, and inferences with their peers, and to thus learn from them. After this discussion and reinforcement of content knowledge, students were allowed more time to explore with their lever materials. Students began replacing the washers with other items, such as textbooks, to see what impact this would have. The freedom to change and integrate new materials into the investigation gave students the opportunity to enhance their own abilities of inquiry.

Pulleys

For this portion of the unit, students explored using pulley kits, similar to Legos, which our school had purchased for use in our science lab. After a brief class discussion that consisted of introducing students to pulleys and brainstorming examples of everyday objects that used pulleys, the students broke up into small groups to begin constructing pulley systems using the kit materials. After groups had explored a single configuration, I asked students to think of other ways they could use the same materials to build a different type of pulley system. Throughout their investigations, I listened to many groups discuss numerous types of pulley configuration and how they could be used to reduce the amount of effort they needed to exert in order to raise different objects. It seemed as though their hands-on experience with the pulleys was able to spark their ideas of how pulleys function, and how they could be used to accomplish various forms of work in our lives. This investigation supported students in developing abilities of technological design. . . , specifically in identifying the trade-offs in using pulleys in one configuration versus another.

Wheel and Axle

For this portion of the unit, I asked students to bring in household items that included use of the wheel and axle (size appropriate). Some examples of wheel and axle items that were investigated by students were: toy cars, door knobs, and old wagon wheels. With permission from parents, students were able to take apart these items to investigate the concept of wheel and axle. This allowed students to learn the subject matter through their own processes of investigation, rather than being told the information by the teacher.

After the initial investigation, students participated in combining both a wheel and axle and pulley system in the construction of a "paper pinwheel." Teams were assigned the task of developing a way to raise a load using wind power as the effort. Because of their initial investigations with these two simplemachines, students were able to trranslate their understanding to developing solutions to this problem with much success.

Inclined Planes, Wedges, and Screws

Because of the relationships between inclined planes, wedges and screws, students spent time investigating these three simple machines as a group, rather than singly. Students examined everyday examples of these three simple machines, such as hardware screws, light bulbs, bottle caps, doorstops, wheelchair ramps, stairs, etc. As in our earlier explorations, students had become skilled at identifying where these machines were used in everyday life. This is an important part of understanding science and technology in society. . . . Students came to realize ways that their quality of life was influenced by the products of technology.

At the beginning of this portion of the unit, students seemed unclear about the initial commonalities among these three simple machines; however, after hands-on investigations and examinations of these machines, students became more confident in their similarities. . . .

Unit Assessment

Assessment of student learning outcomes took place on an on going basis. Throughout the unit investigations, students collected the work they created - these included drawings of different types of levers with labels of concepts and ideas, such as (a) the placement of the fulcrum, effort, and load, along with their observations of different levers; (b) sketches of pulley systems and notes about the effect of the configuration on the effort required to life the load; (c) diagrams of their invented products that used simple machines, along with descriptions of how they worked; and (d) Venn diagrams of their ideas about similarities and differences between inclined planes, screws, and wedges.

As students brought in their own household items illustrating various simple machines and included these in their investigations, they added information about these examples along with their work in a Simple Machines Portfolio. The portfolio served as a tool for students to organize their ideas and keep track of their work, as well as their thought processees. The portfolios also served as a tool for the teacher to document and asses students' developing understanding of the structure and function of simple machines, and their ability to recognize their applications in the world around them. . . .