RPF PREMIUM MEMBER
That's the liquid inside the bouncing ball! I didn't knew it's name! Thanks.Saw this and though I'd add an idea
I think what you want to use is mica powder. A good example can be seen in this video here: https://www.youtube.com/watch?v=3y7HCRnulQE
The stuff comes in all different colors and should give you the effect you want, just get the water to mica ratio correct.