Eli5: How is hydrogen, a potent source of fuel with high energy release, combined with oxygen, a facilitator for combustion and energy release, mix together to make water which we drink like it’s no big deal?

Question

bonus points if you can explain why water has no caloric value, but hydrogen can power huge machinery.

In: 3

Answer 1

Hydrogen and oxygen are each molecules of high available energy, they “want” to react with other molecules to get to a lower energy level. Water is a very low energy molecule and thus the result of most chemical reactions involving hydrogen and oxygen. The low energy level is what makes it so stable. We drink water because it is useful in many chemical reactions that our body must perform to sustain itself.

Now water does not power any machinery, it is the mechanism that allows the machinery to channel power though. Like a hammer it only allows you to nail something, it does not do the work. Water is useful because it’s cheap and available, and when you boil water with a fire you can use the high pressure steam to perform work, the fire is the power source and the water is just the tool