Sometimes you need a new word
Lets say I'm telling a story about some hiker heading up into the mountains. I mention that when passing under a cliff a pebble came loose and landed on him. That might sting but it wouldn't occur to you to ask if he died. Lets say that instead I mention that a boulder had landed on him. Then you'd expect him to be quite dead. That's the nice thing about these old English words that've been around a while and encode distinctions that make sense in our everyday lives. The difference between the pebble and the boulder is just a matter of degree but it's one where the quantitative difference is big enough to become qualitative. If we just had one word whoever I was telling the story to would have to ask questions and because we run into rocks so often I'd know when I'd have to use an adjective. When you're talking about scientific things, though, you don't often have this choice of words. Energy is energy and you're expected to use a ...