Unit 06 · Simple Harmonic Motion
Anything that gets pushed back toward the middle in proportion to how far it strays will oscillate. This unit isolates that condition — a restoring force proportional to displacement — and works out what sets the period of a mass on a spring and a pendulum, how energy sloshes between kinetic and potential, and what the motion looks like graphed against time. Mastery means you can say what a period does and does not depend on, and prove it with a stopwatch.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Restoring force & the SHM condition | Does not connect oscillation to any force. | Knows a spring pulls back but not that force is proportional to displacement. | Identifies the restoring-force condition (force opposite and proportional to displacement) and recognizes it in springs and pendulums. |
| Period & frequency | Uses period and frequency interchangeably. | Relates them but cannot say what changes each. | Predicts how period depends on mass and spring stiffness (and on length for a pendulum) and what it is independent of. |
| Energy in oscillation | Thinks energy disappears at the turning points. | Knows energy converts but misplaces where each type peaks. | Tracks the kinetic–potential exchange and identifies where each is maximum and where speed is greatest. |
| Graphs of SHM | Cannot sketch displacement against time. | Sketches displacement but not velocity or acceleration. | Sketches and relates displacement, velocity, and acceleration versus time, including their phase relationships. |
| Lab technique (period measurement) | Times a single swing; large timing error. | Times multiple swings but does not vary a parameter systematically. | Times many oscillations, varies length or mass systematically, and plots the relationship with uncertainty. |
| Integration (cross-domain) | Treats the science as isolated facts; makes no cross-domain connection. | Names a link to history, reading, or writing but cannot defend why it matters. | Connects the unit to its anchor across History · Reading · Writing (plus chosen electives) and defends why the connection matters. |
“A pendulum’s period depends on its length and gravity — not on the mass and not on the amplitude, as long as the swing is small. I proved it: I plotted period against the square root of length and got a straight line. That’s why Galileo could use one to keep time.”
“A heavier bob swings slower, and if you pull it back further it takes way longer to come back.”
You demonstrate this unit through period-measurement labs plus short oral checks where you reason about what sets the period aloud — not a multiple-choice test. A criterion counts as mastered only when you can both take clean data and justify the physics behind it. Mastery is demonstrated, not awarded.
A 5-page clipboard packet — unit overview, key terms, the mastery rubric, anchor examples, and a score sheet you can print and grade against.