[ethanollin]

Chemistry is not my major, I'm just a nerd who thought putting a lava lamp inside of a PC would look cool , but obviously ordinary lava lamps won't fit the requirement , so I need to come up with my own formula.

The main goal here is to find an additive that can increase the density of mineral oil or wax or whatever makes up the lava part of a lava lamp and makes it slightly denser than water.

Here's the requirement:
1. It needs to work at a relatively low temperature, like just above room temp (40C~50C, cause I don't want to turn my PC into an oven).
Can work on just the heat from the CPU and GPU will be great! (by coupling it on the water cooling pipeline with a heat sink)

2. The additive should be easy to access and not terribly dangerous (either poisonous or flammable).

3. The additive should be clear and colorless.

4. The additive shouldn't damage the plastic (I want to make the container with acrylic or polycarbonate pipe).

Because of the first requirement, I want to replace wax (of the lava part) with something that is already liquid at room temp, hence the title, mineral oil. Before making this post I asked ChatGPT the additive that I could use, the answers I got however are things like carbon tetrachloride, dichloromethane, chloroform etc. chemicals that sound awful just by name and would probably unlive me within a snap of a finger.

So I want to ask professionals on the internet for help before I blindly execute, is there any better alternative or should I just scrap the whole idea?

[Borek]

It is not about smth being denser than water, it is about having two liquids that are 1. immiscible, 2. compatible (don't react), 3. liquid in the reasonable temperature range (don't boil nor solidify), 4. have very similar densities and 5. small changes in temperature reverse which liquid is denser.

Many of these parameters can be checked in books like CRC Handbook of Chemistry and Physics (or their web based equivalents).