[QUOTE=wideman]Here's a neat science project for your next flight. Bring a balloon on board, blow it up to half-full, and tie it. Then watch your seatmate's surprise as the balloon expands to full size as the plane ascends.

Or you can make an El Cheapo Descent-o-Meter™ like I do. Take an empty plastic water bottle, the thinner the better, and cap it very tight at cruise altitude. When they turn off the IFE, you still have something to watch. Slow motion TV substitute on the tray in front of you. Just don't let the FA grab it on a trash run!

At 8000 feet it starts to crush, time to put your shoes on. When it is almost flattened, time to place your seatback in the upright position for landing. When it is crushed, you're landed.