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March 2015 | Tech Tips
Energy Foundations for High School Chemistry
By Michael Tinnesand
Although most students think they have a common sense idea about what energy is, they may find it difficult to give a precise definition, and teaching students about chemical energy can be difficult. This could be because many teachers often postpone discussing energy until late in the year, when topics such as thermochemistry or thermodynamics are traditionally covered, despite energy being a crosscutting concept that accompanies every change in chemistry.
If you need some resources for teaching about energy, you should check out the American Chemical Society (ACS) site Energy Foundations for High School Chemistry: A collection of teaching resources you can trust, to see what it offers.
The module includes content specifically designed for first-year general or honors high school chemistry curricula. It provides animations, videos, and articles that teach concepts of energy in the context of laboratory investigations. Each laboratory activity is accompanied by a Teacher’s Overview document, which includes safety considerations tailored to each investigation.
The idea of a module on energy and the basic content for this project started with a grant from BP and included teacher surveys and interviews. Teachers were asked about what energy topics they could use more support for in their curriculum. They were also asked about what types of activities they would like to see in an ACS-developed site.
Using this teacher input, ACS staff and curriculum developers, including myself, divided energy into four sections and came up with activities to help teach them.
For each of these sections, we developed a set of lab investigations, videos, and demonstrations and included background reading materials.
Connections to standards
In order to make the module as useful as possible, we designed the lessons keeping in mind the Next Generation Science Standards (NGSS), which are based on the National Research Council’s "A Framework for K–12 Science Education." NGSS was developed by 26 states and has garnered support since its publication.
The module can satisfy many NGSS requirements, which include energy in four performance expectations:
- PS3.A Definitions of Energy
- PS3.B Conservation of Energy and Energy Transfer
- PS3.C Relationship Between Energy and Forces
- PS3.D Energy in Chemical Processes
The module, in a nutshell
Each of the components can be used alone or together as a complete set of activities, depending on your curriculum needs. In addition, many of the activities are presented in a format that can be downloaded and modified by the instructor, so they can be tailored to specific needs.
As Richard Feynman said, “It is important to realize that in physics today, we have no knowledge of what energy is!” (1) The first section of the module addresses this exact issue. In What is Energy? various types of energy are explained in the context of how students experience them. Students’ main experiences with energy come when they recognize changes in energy. In fact, it is fair to say that every change we experience involves energy to some degree. We can’t even change our minds without energy! This section introduces the concept of energy by having students investigate a variety of toys and household items, such as a hand-operated music box and a battery-operated flashlight. They are given a list of the various categories and types of energy and are asked to look for what energy changes they witness in the toys. For each change they observe, they suggest the type of energy they think is involved and cite their evidence for their choice. At the end of the investigation, they are asked to come up with an operational definition of energy in their own words. A series of videos and reading selections help them develop their definition into an authoritative version. They also read selected articles from past issues of ChemMatters, an AACT member benefit.
How Do We Use Energy? focuses on the concept of energy in action. One of the best ways to establish a concept is to provide multiple examples of the concept in action. In this section, students investigate energy involved in various chemical and physical reactions. The activities present chemical processes that are familiar to students in their everyday lives but focus on how energy is involved in the changes they observe. These ideas are reinforced with two chemical demonstrations, a video, and a ChemMatters article on the chemistry of explosives. One of the demonstrations is the electrolysis of water, and the other creates a “soda can steam engine.” Students can also watch a video that talks about temperature and energy, phases of matter, and phase change.
In our everyday experience, energy frequently seems to “disappear.” Batteries die, wind-up toys stop moving, and fires run out of fuel. But the reality is that energy is never destroyed, it simply changes from one form to another. How Can Energy Change? offers examples of how energy transfers account for where energy goes in chemical and physical changes and explains the conservation of energy. There are two lab investigations. The first uses thermometers to test the energy change when various liquids evaporate. In the other lab, students collect data while heating water with a Bunsen burner, an electric hotplate, and a microwave oven. A video examines where energy comes from (or goes to) in a chemical reaction. It presents the key ideas that it takes energy to break bonds and that energy is released when bonds are formed. It then explains endothermic and exothermic reactions. Another video presents a career profile in chemistry, featuring a chemist working in biofuels.
What Theories Explain Energy? explores some basic concepts such as entropy and enthalpy. For example, thermodynamics is the study of energy changes that accompany physical and chemical changes. In chemical systems, these changes are described by heat and work, enthalpy, entropy, and Gibbs free energy. These concepts are best understood at the microscopic scale, where the energy can be characterized by the motions of particles and the relative position of particles. While these concepts are abstract, the investigations, videos, and readings in this section give students practical experience with the concepts and rules that govern how matter and energy interact.
In the first investigation, students explore the concepts of entropy and enthalpy through a series of guided procedures involving some simple chemical reactions and physical changes. The other lab investigates the relationship between enthalpy and entropy in a system that couldn’t be simpler: a rubber band. And finally, there is a provocative article called “Why Cold Doesn’t Exist!” from ChemMatters.
I am confident you will find these materials useful and effective when you teach energy. If you have any comments or suggestions about these materials, you can email us at firstname.lastname@example.org.