How to make something that shows how tidal energy works?

Analogy for how a torch works?

• So for my homework I need 3 analogies for how a torch works.Basically an analogy is comparing something to something harder to make you understand something more, for example, comparing your heart to a pump. I need to find one on how an electrical torch works. The one I already have is, having a mine which produces coal for light and energy for a castle. The mine represents the battery, giving out electricity to the trucks which carry the electricity to the castle (the bulb) which uses the coal for light and energy. So basically I just need one more analogy, so any ideas? Thanks x

• Answer:

  Your analogy of trucks carrying coal is not at all how an electric light works, so you might lose points if you use it. Energy doesn't flow from one side of the circuit to the other, it flows around the entire thing simultaneously. All conductors are full of a sloshing sea of movable charges. In a piece of copper wire for example, the electrons jump from atom to atom to atom quite freely, making it a good conductor. An analogy for a piece of wire would be a pipe that's full of water. Batteries are also full of movable charges in the form of electrons in the metal plates, and ions in the electrolyte. An analogy for a battery would be a water pump that is already primed and full of water. A light bulb is also a conductor full of movable charges, but they don't move as freely as those in the copper wire. The filament resists the movement of the charges, gets hot, and gives off light. An analogy for the bulb would be a turbine. Put it all together, and the pump pumps water through itself, in one side and out the other simultaneously. The water moves through the pipes, but the overall flow is resisted by the turbine which turns the flow of water into rotary motion, just like the bulb turns the flow of charges into light. Here's another analogy: Turn a bicycle upside down so you can spin the front free wheel with one hand, and rub it with the other hand. In this analogy, one hand is the battery, the wheel is the conductor (wires) and your other hand is the light bulb resisting the energy flow. Your rubbing hand turns the spinning motion of the wheel into heat and maybe a bit of sound. I believe you can come up with a third analogy given this information. :)