Why aren't there color changing lava lamps?

August 5, 2020 11:09 AM

Okay, so it seems to me like it would be pretty simple to make a color changing lava lamp by having the light bulb in the base be a color changing one--is there something I'm missing? Like do LED lights not produce enough heat?

And if that's true, wouldn't it be relatively easy to design something to get around it, like I don't know, there's one light bulb at the base that heats up the lava and another color changing light at the top?

I'm hoping that there might be a make of lava lamp that one could just trade out the existing lightbulb for one that changes color but I'm guessing that's not possible. Is that right? Would it be possible to rig something like that together? How hard would it be?

Also, why doesn't something like this already exist? Seems like it would be a popular product!

posted by overglow to Grab Bag (7 answers total)

Here's one.
posted by They sucked his brains out! at 11:13 AM on August 5, 2020

Best answer: Your intuition is correct. Traditional lava lamp physics depends on the heat coming from the light bulb. You could either make one with an incandescent bulb and a rotating set of colored gels, or a color-changing LED + a heating element. I don't know if either approach exists as a commercial product.
posted by range at 11:16 AM on August 5, 2020 [3 favorites]

(Or, in the case of the example linked above, you can abandon traditional lava lamp physics and do something else trippy inside the glass jar.)
posted by range at 11:17 AM on August 5, 2020

Best answer: LED's are ten to twenty times more efficient than incandescent filaments, and do not emit in the infrared spectrum. As a matter of fact, their life significantly degrades under higher temperatures, so they would be a bad fit anywhere near a heating source.

You could consider lenses, but then they would get in the way of the thermal heating as well.
posted by nickggully at 11:30 AM on August 5, 2020 [1 favorite]

Do LEDs not produce heat?

As folks have said, no, they don't. The big trend in cities was to replace stoplights and traffic signals with LEDs to save energy. But cities with cold weather seasons discovered that without the heating from normal light bulbs, the signals snowed and iced over and became useless. They had to transition back or find workarounds.
posted by Fukiyama at 11:37 AM on August 5, 2020 [3 favorites]

A motorized color gel might work, like what might be used for theatre, but heat damages gels over time. Instead of using heat, you could change the chemistry of the "lava" inside. You'd need to automate cycling the acidity, though.
posted by They sucked his brains out! at 12:31 PM on August 5, 2020

Or just, you know, use an LED and add a small resistive heating element.
posted by weed donkey at 11:14 PM on August 5, 2020