When tires lock, they slide, providing less friction than when rolling. Sliding friction generally produces a smaller force than static friction. A rolling tire's surface does not slide along the road surface, a rolling tire is static friction. The force of friction depends only on the surfaces involved and how hard they are pressed together. The defroster is made of aluminum alloy.
Crystals are substances in which atoms are arranged in a regular, orderly, repeated pattern.
Small amounts of chemical impurities and imperfections in the crystal structure can alter color dramatically. For example, the mineral corundum is aluminum oxide. It is normally a cloudy, brownish to bluish material. Addition of a small amount of chromium produces a ruby. A small quantity of iron turns corundum into a sapphire.