this post was submitted on 17 Feb 2024
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Showerthoughts

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A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.

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If a machine is never 100% efficient transforming energy into work because part of the energy is converted into heat, does it mean an electric heater is 100% efficient? @showerthoughts@lemmy.world

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[–] ChonkyOwlbear@lemmy.world 165 points 8 months ago (23 children)

You know how you turn on an electric heater and the filament begins to glow? That is energy being converted to light, so not 100% efficient.

[–] userflairoptional@lemmynsfw.com 6 points 8 months ago (2 children)

Black-body radiation is an interesting argument against 100% efficiency, but couldn't you just extrapolate and argue that the emission will be converted back to heat once it stops reflecting and becomes absorbed?

[–] lemmyng@lemmy.ca 4 points 8 months ago (1 children)

That's like arguing that trickle down economics is efficient because the money eventually gets into the hands of the poor.

[–] Phil_in_here@lemmy.ca 3 points 8 months ago

That's like arguing that 99% of the light off a heating element is a laser beam directed straight into deep space.

[–] ChonkyOwlbear@lemmy.world 0 points 8 months ago (1 children)

It depends on the framing of the question a bit. If we are defining 100% efficiency as 100% of electrical energy being converted into kinetic energy (heat) by the device, then that is a no. Some percentage is emitted as EM radiation instead of heat. If they were so then a light bulb or a bomb is a 100% effective heater as well.

[–] CookieOfFortune@lemmy.world 3 points 8 months ago

It depends on what you consider the room: Both a light bulb and a bomb would deliver all their energy around a fully enclosed room. Incandescent bulbs are indeed effective heaters, LEDs just deliver much less energy. And a bomb, by design, is hard to contain in a room.

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