Simple machine: A tool with few or no moving parts that makes work easier
How many kinds of simple machines are there?: Six
Name the six simple machines: Lever, wheel and axle, pulley, inclined plane, wedge, screw
Lever: A bar that rotates around a point called a fulcrum
Fulcrum: The pivot point of a lever
Effort: The force you apply to a machine
Load (resistance): The weight a machine moves
First-class lever: Fulcrum is between the effort and the load
Second-class lever: Load is between the fulcrum and the effort
Third-class lever: Effort is between the fulcrum and the load
Example of a first-class lever: A seesaw or a crowbar
Example of a second-class lever: A wheelbarrow or a nutcracker
Example of a third-class lever: A fishing rod, a broom or tweezers
Inclined plane: A flat sloped surface used to raise or lower loads
Example of an inclined plane: A ramp or a slide
Wedge: Two inclined planes put together to split or cut things
Example of a wedge: An axe, knife or doorstop
Screw: An inclined plane wrapped around a cylinder
Example of a screw: A jar lid, a bolt or a light bulb base
Wheel and axle: A wheel joined to a rod so they turn together
Example of a wheel and axle: A doorknob, a steering wheel or a bicycle wheel
Pulley: A wheel with a rope or chain that changes the direction of a pull
Example of a pulley: A flagpole rope, a crane or a window blind
Fixed pulley: A pulley attached in place; changes the direction of force
Movable pulley: A pulley that moves with the load; reduces the force needed
Block and tackle: A system of pulleys that gives a large mechanical advantage
Mechanical advantage: How many times a machine multiplies your effort
Do machines reduce the work done?: No; they make work easier by changing force or direction
What do you give up when you use less force?: You move through a longer distance
Compound machine: Two or more simple machines working together
Example of a compound machine: Scissors, a bicycle or a can opener
Scissors are made of: Levers and wedges
A longer ramp makes it: Easier to push things up, but you push farther
Work: Force times distance
Wheelbarrow: A second-class lever with a wheel and axle
Pliers: Two levers joined together
Bottle opener: A second-class lever
Stairs: A set of inclined planes
Spiral staircase: A kind of screw shape
Zipper: A group of tiny wedges
Chisel: A wedge
Faucet handle: A wheel and axle
Gears: Toothed wheels that turn each other
Ax splitting wood: Uses a wedge to push wood apart
Drill bit: A screw
Teeter-totter: A first-class lever
Baseball bat: A third-class lever
Hammer pulling a nail: A first-class lever
Why is a longer lever arm helpful?: Less effort force is needed to lift the load
Archimedes' famous line about levers: Give me a place to stand and I will move the Earth

Free flashcards from Peabody at peabody.kids/flashcards/phys-simple-machines