We hear a lot about how movies take liberties with history. Now read about the liberties taken with the physical properties of the actual world:

Flashing Bullets
The terrorist unleashes a lengthy burst of submachine gunfire as the hero runs along a gangway in an industrial plant. Bullets bounce everywhere. This would be a dramatic event for almost anyone, yet moviemakers feel it must be enhanced. The special effects representing impacting bullets give off bright flashes of light. Normal bullets, especially handgun bullets, do not.

Typical handgun bullets are made of copper-clad lead or lead alloys. They simply don’t create bright flashes of light when they strike objects, even if the objects are made of steel. In the chemical industry it’s commonplace to limit maintenance workers to copper-alloy or lead hammers when they are working in areas where flammable fumes may be present. Hammers made of these materials do not produce sparks when they strike objects, while steel hammers can. If you’ve never noticed this phenomenon with steel hammers, don’t be surprised, the sparks generally are barely visible even under ideal lighting conditions.

Intuitor.com

…And so on. The beyond the generalities, the site also turns specifically egregious movies into equally detailed learning opportunites.

[Via digg]