Why would more milk fit onto a penny than water or windshield washer fluid?

Question

ok so we had to do this penny lab and my results don't make any sense i could drop more milk on the surface of a penny than water or windshield washer fluid does anyone have an explanation to this?

Answer 1

It's the difference in "surface tension", this varies with the fluid used and the composition of the fluid.

Milk has a high surface tension; probably the fat content in it. Water has a "medium" tension of the fluids you listed.

Washer fluid is basically water, maybe alcohol, and maybe detergents. Each of these additives will lower the natural water surface tension.