The study of optics and levers, or pressure, is usually reserved for physical science classes. However, these topics are introduced for the first and only time in the seventh grade, so students should learn the principles behind them. Suggestions are made to relate the study of these topics to the eye, muscles, bones, tendons, and heart.

The human eye contains receptors that detect incoming visible light emitted by a luminous object or reflected from an illuminated object. Until the early 1900s physicists believed that the properties of light could be completely understood by viewing light as a wave of electromagnetic energy that was supported by an elusive medium—the so-called ether—that was imagined to pervade even a vacuum. The nature of light still seems mysterious to most people because light manifests the properties of both a wave and a particle. In most experiences geometric optics, which treats light as rays traveling in straight lines, adequately accounts for reflection and refraction, mirrors, and lenses. Before starting these topics, students should be able to measure angles, do ratio and proportion problems, and use gram mass weights and metersticks.

Students in grade seven can and should learn how levers confer a mechanical advantage. Given a lever, students should be able to identify the fulcrum and four important quantities: effort distance, effort force, resistance distance, and resistance force. If three of those quantities are known, students should be able to calculate the fourth quantity. Students can make simple levers and hinges (and other simple machines, if time permits) to show how levers can be used to increase forces at the expense of distances or distances at the expense of forces. Metersticks, weight holders, hooked weights, and pivoted supports are commercially available for students to make a straightforward investigation of the operation of levers. A key element of this standard set is to relate the physical principles to the function of muscle and bone in the body. Pressure, a subject that was introduced to students in the context of atmospheric pressure in earth science, is now discussed in the context of blood pressure and heart function.