Is science fiction a literature of ideas, or of characters? Works that focus on the former often neglect the latter, and vice versa. It's very difficult to examine complex abstractions and ...

Energy close energyEnergy can be stored and transferred. Energy is a conserved quantity. can be described as being in different ‘stores’. Energy cannot be created or destroyed. Energy can be ...

A lever is a simple mechanism that uses a bar to pivot around a fixed point called a fulcrum. Levers can be joined together to form linkages. Simple linkages can be used to change the direction of ...