Unit 04 · Energy & Work
Energy is the currency of physics — the quantity that is transferred and transformed but never lost. This unit defines work as force acting through a displacement, builds kinetic and gravitational and elastic potential energy, and then uses conservation of energy to solve problems that would be brutal with forces alone. Mastery means you can track energy through a system, account for what friction removes, and reach for conservation before you reach for kinematics.
| Criterion | Not yet | Approaching | Mastered |
|---|---|---|---|
| Work | Thinks any force applied does work, regardless of motion. | Computes work but ignores the angle between force and displacement. | Calculates work correctly with the force–displacement angle and explains when work is zero, positive, or negative. |
| Kinetic & potential energy | Confuses the two or omits units. | Computes each separately but mishandles the reference height for potential energy. | Computes kinetic, gravitational, and elastic potential energy and chooses a sensible zero for potential energy. |
| Conservation of energy | Does not see energy as conserved; treats each step separately. | Applies conservation but forgets energy lost to friction. | Tracks energy transformations through a system, including thermal losses, and solves with the conservation principle. |
| Power | Confuses power with energy or force. | Uses the power equation but not in context. | Relates power to the rate of energy transfer and compares real devices by power output. |
| Lab technique (energy on a ramp / spring) | Takes single measurements with no check on conservation. | Measures heights and speeds but does not compare energy in to energy out. | Uses a ramp or spring to measure energy at two points and tests conservation against loss, 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. |
“At the top the cart is all gravitational potential energy; at the bottom it’s mostly kinetic, but not all — friction turned some into heat. So I set potential at the top equal to kinetic at the bottom plus the friction loss, and I don’t need the acceleration at all.”
“It has more energy at the bottom because it’s going faster, and power is just how strong the push is.”
You demonstrate this unit through energy-conservation labs plus short oral checks where you trace energy through a system 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.