How a Car Can Run on Hydrogen and Only Drip WATER

Some cars run on hydrogen and leave nothing behind but a trickle of clean water.

There's no burning, no explosions, and no engine in the usual sense at all. So how does a tank of hydrogen gas actually turn into electricity?

Inside a fuel cell, hydrogen is fed in on one side and oxygen from the air on the other. A special membrane sits between them. It lets the hydrogen's protons pass through, but blocks its electrons. Forced to take the long way around, those electrons flow through a circuit, and that flow is electricity. On the far side, the protons and electrons reunite with oxygen, forming pure water.

That means the only thing coming out of the tailpipe is water clean enough to drink. The car is essentially running on the most abundant element in the universe, and quietly exhaling a glass of water.

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