Friction describes how objects move when they are subjected to a force or another material, such as the air or water. Friction exists in every part of nature, and the most common forms are static and kinetic . The more force we apply, the greater the amount of friction we experience If you are shaking your body in front of a wall, it will be much harder to move than if you were standing on one leg. You will still hit some surfaces like a tumbling rock, but not as hard as it would be if you stood side by side against it. So when a person stands against a wall, friction applies even though he or she is still moving around. This occurs because your gravity is too big for you to feel as a result of gravity pulling the wall back against itself. It’s not just moving objects that cause friction: moving things also have friction if their mass exceeds their gravitational pull(as in airplanes) or if they fall into air (as with rockets). So friction can be described as a reaction force that causes a change in motion. For example it may occur between two metal plates that are pressed together by hand. The surface area and location of each plate determines this type of friction but both sides will undergo friction when touching. There are four different types of friction.

1.Static Friction

Static friction is the only kind that is always present between two objects and is therefore called friction in its purest type. It arises spontaneously for all objects, including people, animals, and even some matter. Examples include shoes rubbing against a tile floor, the bottom of a pool from which water rises up, the surface of concrete facing an aeronautical turbine, or ice skating rinks against a lake. Static friction is also sometimes called frictional friction (vibrating wave), and is usually found at the boundaries of materials. In fluid flow, this friction is due to the pressure difference created by incompressible fluids. These forces are caused by either density differences, temperature differences, or friction between gas and liquid. For most things where we experience little or no static friction, we call static friction friction a second-order effect. When there is only a small amount of motion or interaction occurring between two objects, such as when two stones are moved against each other and then become stuck together, there is less friction Instead kinetic friction.

2.kinetic friction

kinetic friction is found only where motion occurs. But for objects that are moving vigorously, kinetic friction can cause a drastic change in speed, direction, or position. Examples of kinetic friction are moving vehicles against wheels which spin them or two planes against each other and cause small changes in velocity and position. Also, objects moving through liquids without having friction will rise up and then fall down as their movement through the liquid depends on the fluid friction. When lighting up an airplane, friction means that the engine, lights, and the controls are constantly moving as the plane moves overhead. To create a vacuum inside a glass bottle on a table, friction causes the object to vibrate. Vibrations are always accompanied by sound like a violin playing its melody. As the bottle vibrates more the noise increases as gravity causes friction. Kinetic friction is also what happens when two spheres collide against each other, and then touch surfaces and then collide again. Such collisions cause vibrations and sometimes sounds. So to create the space below a bed, friction would mean bringing back the bed to its original place with just enough room to slide underneath of the bed. The resulting friction prevents the object from falling out of bed. To keep the objects off of the bed, friction would prevent you from going over the edge of the bed. A ball being thrown over a wall, then crashing onto the ground is what gives us kinematic friction. And the same applies to those parts of our body that have kinetic friction. A bump on your shin causes increased blood flow to the pad. If the bump was made by an electrical current, resistance would occur between the pad and skin. Because friction is caused more easily then electric currents, we call friction a dissipative effect.