Our curriculum uses two underlying concepts to unify the sciences as an extended investigation into a broad range of systems ranging from the solar system, the Earth, life forms that inhabit our planet, and so on. Too often, science is presented as a series of disjointed facts, and we fail to make the connections between the concepts of various disciplines. In reality, all scientists are knowledgeable biologists, geologists, astronomers, chemists, and physicists. We have developed our curriculum upon two important themes: Matter and Energy, building on work of Goldberg et al. [Goldberg, F., Otero, V., and Robinson, S. (2007), Physics and Everyday Thinking, It’s About Time Publishing.] and Nelson [Nelson, G. (2008), “Physics and Everyday Thinking as a Model for Introductory Biology and Geology Courses,” presented at PTEC-Northwest Regional Conference, Seattle, Washington: October 10, 2008] to extend this analysis to all the sciences.
Often, we teach the term of energy and the idea of conservation of energy without developing why it is important or how it manifests itself. Consider the question shown here from the state of Texas’ 2006 TAKS test. It concerns the topic of energy, specifically the conservation of energy and how it can be transformed from one type (gravitational potential energy) to another (kinetic energy). It is answered correctly by 85% of students in a pre-test to our pre-service elementary teachers’ class, indicating their successful training over years on this kind of problem.
Yet, students mastering this question can fail to apply a basic understanding of energy to other systems. A common student misconception is that a light bulb grows warm when connected to a electrical circuit because the battery to which it is connected is hot, therefore a source of thermal energy. Such a misconception misses the basic forms of energy and how energy can be transformed from one type (electrical or chemical potential) to another (light and heat). Another common student misconception is that a cup of coffee cools because "more cold gets in to it"; instead, students should recognize thermal energy as a form of energy that is transferred to the surrounding air in the room, and pause to consider the source of the thermal energy in the coffee in the first place.
Likewise, we teach "matter" in our curricula, but more as a term than as a model with which we explain a host of phenomena around us.
Consider the TAKS question at left which, according to standard curricula in chemistry, is properly answered as “F,” a “compound,” but would be answered by any practicing physicist as “M,” a molecule or by many geologists as “K,” a mineral. If students cannot wade through the jargon, it is unlikely that they will come to understand the basic fact that all of physics, chemistry, geology, and biology depend upon the atomic or particle model of matter.
Rather than emphasize terminology, it is important to use the particle nature of matter to explain phenomena. The coffee cools, for example, because of collisions between particles in the coffee and particles in the air. The drum, for example, transmits sound to our ears by converting the kinetic energy of the mallet to the kinetic energy of the drumhead, which in turn causes collisions of particles in the air, a domino effect that finally reaches our ear. The seedling, for example, becomes a tree because it takes in carbon from the surrounding air. This last example is particularly poignant, because when students in our courses are initially shown a large chunk of wood and asked “where does all the stuff in this chunk of wood come from; in other words, from where does a tree acquire all its matter?” many will promptly respond “water” and “sunlight,” and many will reply “the soil.” Only 15% correctly cite the carbon dioxide in air. Yet, 90% of our students correctly answered “C” to the question of which chemical compound represents the food energy in this process.
Energy is an important fundamental concept in science, and so it appropriately acts as a common linking thread throughout the Hands-on-Science curriculum. In the first course we spend a significant percentage of our time discussing how energy flows from one form to another in physical systems. That idea is applied in other courses after the foundation of energy flow and energy conservation has been laid out. Energy, force, and energy conservation must be understood before concepts like how buoyancy can be developed since it builds upon an understanding of balanced vs. unbalanced forces. By the time we end the third course, which discusses energy in biological systems, participants are quite comfortable discussing topics such as how radiant energy from the sun becomes chemical energy in plants (ex., photosynthesis) or thermal energy in our atmosphere (ex., greenhouse effect).
As we learn about gravity as a force and how it is related to gravitational potential energy and conservation of energy, we develop ideas about how the force of gravity depends on mass. Later, we build upon these concepts to understand gravity beyond earth, which then allows us to talk about planetary orbits.
Throughout discussions of physics, chemistry, and biology content, we build on the small particle model of heat movement (conduction and convection) to explain the third method of heat movement: radiation. This is interesting because it is a departure from explaining heat movement though a medium (solid, gas, or liquid) and instead explains movement through a vacuum. The whole topic is necessary because the biology workshop delves into a discussion of energy entering living systems, and this energy comes in the form of visible light traveling to Earth from the Sun through the vacuum of space. Without an understanding of the small particle model, we would have no context for developing our ideas of radiation.
The study of fossils is another topic that builds upon content from multiple disciplines. In our geology discussions, we learn that different geologic strata can be identified by their similar fossils. This emphasizes the layering of the Earth and also the long time spans involved in the Earth’s history. In our biology work, we discuss fossils as examples of the tremendous variation of organisms present on the earth at different times and build upon the previously developed concepts to explain the diverse lineages that can be traced through time to today.