If I had a small bucket of water (12 inches in diameter) and I wanted to slow down the speed that waves travel across the bucket, like when I tap the side of the bucket, what non-toxic and clear chemicals would be good to add to slow down the waves?
If there aren’t any that are non-toxic and clear, then non-toxic and opaque would be the second choice.
It would be nice to cut the speed substantially, like maybe to 25% or even slower.
That was quick, thanks.
You’re most welcome; it’s what McDonalds uses in their shakes. BTW if you ever want to go rafting in Utah, PM me.
Now that that’s solved, is there a way to speed up waves in water? Would this be equivalent to making the water less viscous?
Heat it. Yes, it does.
Interesting. How does heating the water make it less viscous? 
By giving the molecules more energy making it easier for an external force to overcome the forces between the molecules.
I get it! That makes perfect sense. Heating the molecules “gives them more energy” = more energetic. Which makes it easier to break free of the attraction other molecules exert on it. Correct?
Thanks, naita! 
Very slowly, down rivers of guar gum.