American Scientist

Force is the common agent by which a physical object is held in place or moved, and is related to mass and motion through Newton’s second law. Forces, alone or in combination, effect and affect every action imaginable: balancing, batting, bouncing, carving, catching, cutting, falling, floating, flying, grabbing, gripping, grinding, ratcheting, rolling, rotating, skidding, slipping, sliding, spinning, teetering, throwing, tumbling, turning, twisting, starting, and stopping. I don’t recall appreciating as a child that force was behind every action I initiated and every reaction I responded to at home, at play, or at school. I must have had some vague notion that something I now recognize as force had to do with contact between me and the object involved, because I saw, felt, and heard something common between playing stoopball, stickball, and touch football. Indeed, we train our muscles in the rules of force by playing games of all kinds, including marbles, jacks, jump rope, and hopscotch, not to mention partaking in playground activities on seesaws, slides, and swings. The forces involved in our childhood activities become so familiar to us that we hardly think of how complicated they really can be.