The lid has a metal button which is pushed in. The button is pushed in because a small number of air molecules push from inside, but a large number of air molecules push down on the outside of the jar. When I open the jar, air enters, so that the forces are equal and the button pops up. P2 displays a poster with the equation for pressure on it. We've been talking about the force exerted by molecules, but now is probably a good time to introduce the idea of pressure.
Pressure is defined as the ratio of the force exerted to the area the force acts on.
This is getting a little too complicated. Here's a question. But let's say for the sake of argument that you had to chose one. I'd choose the woman. The woman's weight is concentrated all in one tiny spot.