Achild slides down a slide on the playground and her hair starts to stand on end. what happened?

It's static electricity from sliding down. Whenever a person goes fast on something, (say a roller coaster/slide/etc...) their hair gets filled with static electricity. Have a good day! :3 

Possibly static electricity, I'm not so sure you should rely on my answer, but it's a guess.

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The answer is water molecules are split.cellular respiration and photosynthesis are complement  reactions to each other. these are reverse reactions. in cellular respiration glucose and oxygen yield water and carbon dioxide. so, when respiration begins,  glucose molecules are split. in the opposite reaction - in photosynthesis, carbon dioxide and water yield glucose and oxygen. thus,  when respiration begins, water molecules are split.