Chapter 10 — Science & Nature
How does photosynthesis work?
Plants use sunlight to combine water and CO₂ into sugar (glucose), releasing oxygen as a byproduct. Chlorophyll captures the light energy. Essentially every calorie humans eat traces back to this reaction.
Follow-up questions
Why are leaves green?
Chlorophyll absorbs red and blue light for the reaction and reflects green — so we see what it doesn't use.
Do plants sleep?
They have circadian rhythms — leaves droop at night, some flowers close. Not sleep in the animal sense.
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