What’s in This Unit?
Scientists continue to devise new ways to harness human energy. Energy-harvesting backpacks, bikes, rocking chairs, and knee braces are just a few of the innovative devices that have been created to capture human energy and use it to power electrical devices. In this unit, students assume the role of student energy scientists in order to help a team of rescue workers with an energy problem. Students work to find a way to get energy to the batteries in the rescue workers’ electrical devices, even during power outages, and this serves as the design problem for the unit. First, students are motivated to explore relationships between different types of energy—with an emphasis on kinetic energy and potential energy—and the ways energy is transferred and converted. To solve the rescue team’s energy problem, students research various ways to capture and store energy. Then, students apply their knowledge about energy to design an energy system that can use human kinetic energy to power an electrical device.
We chose the context of harnessing human energy for this unit, the first of a year-long physical science (or integrated science) course, for several reasons. First, it provides students with the opportunity to dive into a current topic that is on the frontier of technological innovation. People are devising innovative and sometimes surprising ways to capture human energy to power electrical devices. Some of them involve cutting-edge science, such as clothing that gathers energy from static electricity each time the fabric flexes. Some methods use tried-and-true technology in new ways, such as incorporating an electric generator into a backpack or a shoe. What’s particularly exciting in this do-it-yourself era is that inventions are being created not just by scientists, but by non-scientists, some of whom are as young as your students. It’s both inspiring and empowering for students to read about, for instance, a 15-year-old girl who invented a flashlight powered by the heat of her hand.
Another reason for focusing on harnessing human energy is that the subject of energy is important and ubiquitous; it runs through all of science and engineering. This unit capitalizes on students’ intuitive ideas about energy—that energy makes things go or makes things happen— and advances those ideas to include an understanding that there are different types of energy—in living systems, in physical apparatuses, in fuels—and that all of these types of energy are forms of the same thing. This unit is designed to help students build a useful framework for their understanding of energy and provide an invitation to explore, leaving students with questions that will be addressed in future units.
The first chapter of the Harnessing Human Energy unit introduces students to their role as student energy scientists at the Energy Research Lab. They focus on foundational energy concepts that they will draw on to design an energy solution for the rescue team. Students explore the Harnessing Human Energy Simulation and use physical materials to build energy systems. Students are introduced to the categories of potential energy, kinetic energy, and light energy, and read about inventors who are applying ideas about energy to design cutting-edge energy innovations. These activities are intended to help students build on what they intuitively know and have heard about energy, and make the transition from thinking about energy in an everyday sense to thinking about energy as scientists do.
In the second chapter, students investigate energy transfer: in order to figure out how the rescue workers can get energy to the batteries in their equipment during rescue missions, students need to know how objects get energy. Students use the Simulation to learn about how energy is transferred. Once they have established that when something has energy, the energy must have been transferred from something else, students research possible sources of energy for the rescue team. To conclude Chapter 2, students write a report to the rescue workers explaining how they can get energy from an energy source to the batteries in their equipment during rescue missions.
In the final chapter of this unit, students converge on human-powered generators as the best source of energy for the rescue team. Working in groups, students design and build physical models of energy systems that harness human energy. As a culminating experience, students apply the expertise they’ve gained as student energy scientists to evaluate evidence and critique an energy-harnessing device that has been proposed as an energy solution for a school.