They should build the batteries of what they think is inside them and use it to power a LED or something. See how long it lasts.,(reply>), @Simon Would be awesome if you can make a DIY demonstration on your YouTube, I'm sure the views would be a lot.,(reply>), It would be crazy if this lasts forever due to some thermal gradient. I feel like I just saw an explanation of this in the last couple of weeks -- how/why the ball bounces back and forth. I think both are charged differently but then when it touches the other it discharges and becomes the same charge which repels itself and becomes attracted to the other side and the process repeats. It might have been veritasium that showed it with falling water.,(reply>), @Rapta I assume they likely built the bell around the output of the battery. Given it's very little, they likely experimented with what they can do with it and settled on this bell design. So it's not like they were trying to save power, but just figuring out what they could do with what they had.,(reply>), @Simon I'd say it's more likely that the voltage being used is a result of the batteries outputting that high of voltage rather than an intentional power saving design. But ohm's law was discovered slightly before this bell was built so I very well could be wrong.,(reply>), @Simon Did not know that. Thank you for sharing.