Newton's First Law of Motion states that an object in motion tends to stay in motion unless some external force slows or stops it. The force of friction slows objects in motion and reduces the energy behind them. For example, when a kid on a bicycle stops pedaling, the bike slows down due to the friction between the tires and the sidewalk. Friction also creates heat, as when a person rubs their hands together.
Advantages of Friction in Weather
Meteorologists found that friction decreased surface wind speeds, making them less volatile. Friction also encourages surface air masses to merge and rise, which aids the rain cycle. Rough terrain, trees and buildings create the friction that acts on wind speeds.
Advantages of Friction for Animals
Friction between animal's feet and the ground makes running and walking easier. In fact, without friction, animals would have difficulty standing. It's like the comic scenario of someone slipping on a banana peel: If there's no friction, people and animals couldn't walk; they couldn't plant their feet firmly on the ground. There would be no friction (i.e. traction) to keep their feet from slipping and sliding all over the place.
Advantages of Friction in Everyday Life
In everyday life, friction between the road and a car's tires help the driver control the vehicle's speed; by applying the brakes, you slow the car to a stop. Friction also makes writing on paper possible. When using a pencil, the paper's friction causes the pencil lead to rub off. When using a ballpoint pen, friction triggers the ball to roll, thereby releasing the pen's ink.
Advantages of Friction in Space Sciences
While in space, meteors and comets have no force to slow them down. As they hit the Earth's atmosphere, however, not only does the atmosphere's friction slow them down, it tends to break them apart into smaller pieces, thereby lessening their impact on the Earth's surface.
Advantages of Friction in Welding
Friction welding works by using a compressive force along with friction-induced heat to join two surfaces together. The friction-induced heating softens the metal components to make them moldable, at which point the motion needed to create the friction is stopped and the compression force is applied until the joint between the two components cools. This method of welding allows different materials to be joined together (for instance, wood and metal) and increases productivity in manufacturing industries.
Advantages of Friction in Camping
In a camping or survivalist setting, friction can been used to start fires. Friction created by rubbing two pieces of wood together heats the wood until it reaches combustion temperature (around 425 degrees Celsius or 800 degrees Fahrenheit) and catches fire. For this to work, the wood must be quite dry and have little or no resin present.