How can someone lift a very heavy load? If one could slice the load into pieces, that would trade increased distance for decreased effort. But since one can't break things because they are so heavy, the inclined plane comes into play.
The Inclined Plane
The Lever
Mechanical Advantage and Friction
The Screw and the Wheel
The Pulley
Molecules in Solids
Molecules in Liquids
Evaporation and Condensation
Expansion and Contraction
Measuring Temperature
Temperature vs. Heat
Atoms
Electrons
Conduction
Volume and Density
Buoyancy
Convection
Heat as Energy
Radiation Waves
The Radiation Spectrum