A simple machine is a basic mechanical device that changes the direction or magnitude of a force, making work easier. They are the building blocks for more complex machines. There are six classic types of simple machines:
1. Lever: A rigid bar that pivots around a fulcrum to lift or move loads (e.g., seesaw, crowbar).
2. Inclined Plane: A flat surface set at an angle to help move objects upward with less effort (e.g., a ramp).
3. Wheel and Axle: A circular object (the wheel) connected to a smaller cylindrical object (the axle) that work together to reduce friction (e.g., doorknob, car wheels).
4. Pulley: A wheel with a rope or cable that changes the direction of a force, often used to lift objects (e.g., flagpole, crane).
5. Wedge: A device with a sloping surface that splits objects apart or holds them in place (e.g., axe, knife).
6. Screw: An inclined plane wrapped around a cylinder, used to hold things together or lift objects (e.g., a jar lid, drill bit).
These machines reduce the amount of force required to perform a task, but they do not reduce the total amount of work done.