[delichon]

Advantages of a business card sized hollow box partially filled with water:

  * more realistic fluid motion
  * cheaper, easier build
  * easier to debug

Disadvantages:

  * risk of wet butt when you sit down
  * less joy of doing hard things

[jrowen]

* less joy of doing hard things

Have you tried to fabricate such a box? I wouldn't be so sure.

[pfortuny]

It also solves a fluid mechanics problem much faster and more accurately than de digital one!

[animal531]

I love good finger toys at my desk to keep my ADD busy while I'm working. They need to be:

- Light: If they make a clanking noise every 5 seconds when you pick them up and put them down its just distracting.

- Plastic: There are other materials that work, but in general metals and fabrics react too strongly with your fingers over time, whereas plastic can be easily cleaned.

Having a little water window isn't a problem, but the water is also not as directly cool looking. Usually in the '90s you'd get those mixed color oil/water toys where the colors would make them stand out more, but shaking them would mix the substances causing them to lose function.

As such the electronic version is quite durable in comparison.

[kazinator]

Disadvantages:

  * excessively fast fluid motion at card scale

[N2yhWNXQN3k9]

increase viscosity of said fluid

[kazinator]

It doesn't work that way, unfortunately. The virtual fluid represented by the LEDs does not move anything like syrup. It's like looking at a small image of water sloshing in a big tank.

To get of fluid to behave that way on the scale of several inches, the fluid would have to be massive (very dense) while simultaneously gravity would have to be reduced.

[bullox]

> the fluid would have to be massive (very dense) while simultaneously gravity would have to be reduced.

/joy of doing hard things intensifies

[dragonwriter]

> It doesn't work that way, unfortunately

It works exactly that way.

> To get of fluid to behave that way on the scale of several inches, the fluid would have to be massive (very dense) while simultaneously gravity would have to be reduced.

No, it would just need to be very viscous. Viscosity is literally resistance to flowing, density is not, and a less dense fluid can nevertheless also be more viscous (honey is less dense than saltwater, but saltwater is much less viscous at STP [standard temperature and pressure, 0°C and 1atm], while mercury is significantly more dense than granite but something like 23 orders of magnitude less viscous at STP.)

[N2yhWNXQN3k9]

Viscosity is literally a function of how a fluid behaves, but okay, whatever, probably a good take

Defined as:

> a change in shape or to movement of its neighboring portions relative to one another

[wedesoft]

You can use two different fluids instead of water and air.

[mhb]

Starting point: Ocean waves in a bottle

https://www.youtube.com/watch?v=W4jbx5WLhy4

[kenny239]

things you get away with when you remove one level of simulation...

[bravesoul2]

* no rust

[chr15m]

Unless the case is iron.