Define and distinguish conduction, convection, and radiation, and classify real examples of each.
Conduction is heat moving through direct contact, as fast-vibrating particles in a warm object bump their slower neighbors, passing energy along -- a metal spoon left in hot soup gets hot up its handle. Convection is heat carried by the movement of a fluid itself -- warm fluid becomes less dense, rises, and cooler fluid sinks in, creating a current.
Radiation is heat carried by electromagnetic waves and needs no matter at all to travel through -- it crosses the vacuum of space, which is how the Sun's warmth reaches Earth. Near a campfire, all three can happen at once: radiation from the flames, convection in the rising warm air, conduction along a metal stick left resting in the fire.
Mastery looks like: They correctly classify a real example as conduction, convection, or radiation and explain what is physically happening.
Common stumbles: Confusing convection (fluid movement) with conduction (direct contact); assuming radiation requires visible fire rather than any electromagnetic heat transfer.