Question

Which experiment best shows water’s ability to act as a solvent?

Answer 1

Ahhh kill me. I just typed a beautifully long response for you, but somehow backspaced out of the page.

Answer 2

I can't find the motivation to type it again. Here is a brief summary of what I tried to convey.
1) water has a specific heat for a liquid and thus can be boiled to high temps without vaporizing. Higher temp makes things dissolve faster, due to diffusion.
2) water is one of the most polar molecules on earth. Knowing the rule like dissolves like means most polar and ionic substances will dissolve in water, with few exceptions.

An experiment would be to dissolve sugar cubes (polar molecules) or salt crystals (ionic) in water, which will dissolve very easily.