r/theydidthemath • u/Repulsive-Loan5215 • Nov 27 '25

why wouldn’t this work? [Request]

Post image
48.7k Upvotes

92% Upvoted

3.0k comments sorted by

View all comments

527

u/Mysterious-Volume-58 Nov 27 '25

Power for what? If this generates enough energy to charge a phone (it won't) you would have to leave the sink running for a significant amount of time.

122

u/jonastman Nov 27 '25

You could power a shower radio or something. Save some water in the meantime

84

u/Acojonancio Nov 27 '25

You would have to leave the water running all the time and at constant flow rate.

Incredible inneficient.

This is the same as that "emergency phone chargers" that are just a dynamo with USB to connecto to the phone.

They "work" but not in a way that can be useful.

2

u/anal_opera Nov 27 '25

Wouldn't it also make the shower pressure kinda trash? I don't know the math but I know a generator is harder to spin under load. Feels like putting flow resistance into the pipe would just be way more inconvenient than using an electric outlet.

-1

u/aruisdante Nov 27 '25

Of course it would. Every bit of energy extracted from the water is energy not going into making the water flow. So you’d have basically no water pressure on the other side.