working model for harnessing energy? Answered

Harnessing the energy - of horses.

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• rubber-band powered airplane/boat/whatever (kinetic energy stored in/relased by spring (e.g. rubber band))
• any container with a chute or spigot at the bottom (gravitational energy)
• hand-cranked radio/coffee grinder/anything (physio-mechanical/kinetic)
• pinwheel or whirligig (wind energy/kinetic energy)
• toilet (waste is transported away by hydraulic energy)
• solar oven (solar energy)
• coffemaker (electrical energy is tranformed to heat energy, heat energy boils water & produces steam energy, steam energy lifts water up into brewing chamber, gravitational energy pulls water through brew basket into coffee carafe).