What makes balls move?

Children play with balls in many different ways. They throw them, catch them, kick them, and roll them with seemingly endless delight. We are learning how natural forces, such as gravity and friction, affect the movement of balls. We discussed the meaning of force and how we can use it to move a ball. Using forced air from a blow dryer, we discovered how the air can affect a balls movement. Then, I gave each student a straw and pom pom balls to move with our breath. We discussed how the ball's weight or how hard air blew made a difference in the distance traveled.