Where does the energy come from to lift water by osmosis? (feddit.uk)

submitted 2 weeks ago* (last edited 2 weeks ago) by Robbo@feddit.uk to c/asklemmy@lemmy.ml

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For example in a tree, the water is lifted from the high concentration in the soil to the low concentration higher up in the tree. But at the end of that process the water has been elevated, which should take energy (=mgh), but it seems like it kind of gets lifted for free without spending any energy?

Similarly, dipping a paper towel into a bowl of water, the water "climbs" the towel (by capillary action?) and absorbs upwards, meaning the water was lifted upwards (so gained potential energy) seemingly for free?

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[-] petl@feddit.org 20 points 2 weeks ago

No energy is required for regular osmosis as it is a statistical proces involving the random movement of particles: https://www.sainaptic.com/post/what-are-the-differences-between-diffusion-osmosis-and-active-transport

Trees have a vascular system for water transport: https://www.earthdate.org/episodes/how-trees-lift-water

The energy required for a piece of paper to get wet upwards is provided by the reduced surface energy: https://physics.stackexchange.com/questions/2254/when-water-climbs-up-a-piece-of-paper-where-is-the-energy-coming-from

this post was submitted on 31 Oct 2024

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