Where do you think trees come from. Where does the material they are made of come from. The ground, right? Well, actually only part of it: The water. The "hard" part, the carbon, comes out of the air!

The tree takes carbon dioxide from the air (that we animals breath out) and water from the ground and, using photosynthesis, creates "wood" from it - thereby, basically, storing the sun's energy and producing the oxygen we animals so desperately need, as a byproduct.

Then, when we burn the wood, the energy gets released again, using up oxygen and producing carbon and, yes, water vapor - emitted as smoke.

Fascinatingly from a chemical point of view photosynthesis and combustion are the exact opposite - here are the chemical formulas:

Photosynthesis: 6CO2 + 6H2O => C6H12O6 + 6O2

Combustion: C6H12O6 + 6O2 => 6CO2 + 6H2O

Isn't this a wonderful cycle of life? The interplay of plants and animals, one producing the gas the other needs and vice versa. The trees, storing the warmth and light of the sun, giving us the opportunity to release both again later as needed.

And all made beautifully comprehensible by science!

Another example of how science does not take away but add to the beauty of nature by making it visible also to the mind.

PS: Thank you Mr. Feynman for the wonderful story that inspired this post!