center of gravity

The counterintuitive demonstration in the video is a beautiful example of the concept of center of gravity. It sure looks like the fork and spoon should immediately teeter off of the glass and crash onto the table. And its even more dramatic when half of the matchstick burns away but the contraption still balances on the edge of the glass. But its all physics.

In the evolution of ride-over-anything mountain bikes, the ever-vulnerable rear derailleur—that gangly parallelogram that shifts the chain up and down the rear cogs when it´s not clogged with mud or bent by rocks—has been a glaring technical handicap. So GT (gtbicycles.com) got rid of it. With its $5,000 IT-1, GT moves gear-changing duties to an unsullied haven inside the bike frame, by way of an eight-speed internal transmission.