Can you help me make home brewed magnesium? [more inside]
posted by sipher on Dec 3, 2006 - 6 answers

So sharks can smell one part blood in one million parts seawater. How? I understand that the blood would diffuse in water, but wouldn't at least a particle of the blood have to come into contact with the shark? Does diffusion happen that fast?
posted by Coffeemate on Jul 12, 2004 - 11 answers