We learned in the first part of the class that when an object had a velocity that it moved a distance proportional to the time: x = vt. A glob of diffusing molecules spreads but does not follow this law. State the law for how a diffusing distribution spreads and explain why it is different from the velocity law given above.

Note: This is an essay question. Your answer will be judged not solely on its correctness, but for its depth, coherence, and clarity.