- Force: Pushes or pulls that can cause objects to move, stop moving, change speed, or change direction.
- Friction: A force that opposes the motion of an object.
- Simple Machine: Devices that change the direction or size of a force.
- Compound Machine: Devices that contain more than one simple machine.
Simple Machines:
- Lever: A bar that rotates on a pivot or fulcrum. Example: Shovel.
- Inclined Plane: A flat, slanting surface. Example: Ramp.
- Wedge: Two inclined planes placed back to back. Example: Axe.
- Wheel & Axle: A fixed wheel turning on a rod through its center. Example: Wagon wheel.
- Screw: An inclined plane wrapped around a cylinder. Example: Jar lid.
- Pulley: A wheel with a grooved rim and a cord around it. Example: Flagpole pulley.
Compound Machines:
- Combine two or more simple machines working together.
- Examples: Wheelbarrow (lever, wheel & axle, inclined plane), Scissors (lever, wedge).
Pushing & Pulling Forces:
- A push moves things away; a pull moves things close.
- Gravity is a force that pulls everything toward Earth (e.g., apple falling from tree).
Parent Tip: Review the logic above to help your child master the concept of simple and compound machines worksheet.
