Soccer physics explains why the soccer ball curves, why it bounces, and how high it goes, as well as how the pressure in the ball affects the bounce or kick of the ball.  Newton's First Law: An object at rest tends to stay at rest and an object in motion tends to stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force. That applies to juggling a soccer ball because the unbalanced force could be gravity or wind; but in this case it is the player's foot, head, leg, or shoulder. The player will use his or her leg to kick the ball into the air. Since the ball is at rest, it will continue to be at rest until the player comes in contact with the ball to start juggling. The reason for the ball to stop is friction, and Earth's gravitational pull. Newton's Second Law: The rate of change of momentum is proportional to the imposed force and goes in the direction of the force. This simply means, in the physics of soccer, that if the soccer ball has a lot of mass, it will require more force to accelerate. If the ball has little mass, it will require very little force to accelerate when the soccer ball is juggled.  Newton's Third Law: For every action there is an equal and opposite reaction. This means when you kick the ball into the air it will kick back at you just as hard. The only reason you don't feel or realize this, is because our legs have more mass, meaning more inertia, which is the resistance to move according to the physics of soccer.