Liquids, gels, and aerosols on a plane

Last week I was sitting around with some people in a bar in San Francsico and we were trying to figure out the TSA’s regulations on things on planes.

Snakes are OK, as we know. Solid foods are OK. Laptops are OK, except Dell and Apple laptops on Quantas and Virgin (this because of the Sony batteries that some, but not all, models use).

But what about sort of intermediate things? What about gummi worms or avant-garde culinary foams? I can’t take a can of shaving cream with me, but could I squirt it into a bag and take that? What about oranges? If I take an orange into the screening area, and then juice it, does it suddenly become prohibited? It’s manifestly the same thing, but it’s changed phase to a prohibited phase. Same with ice, really. Since solids are OK but liquids are not, could I bring a bottle of ice onto the plane and let it melt so I could drink it? Would an icee or slurpee be acceptable, or does that count as a liquid?

Crucial issues here, folks.