Lesson 7 of 10
⚙ Simple Machines
What You'll Learn
- Name the 6 types of simple machines
- Understand how a lever creates mechanical advantage
- Interact with a virtual lever balance to see how distance affects force
The 6 Simple Machines
A simple machine is a device that changes the direction or size of a force. There are 6 types:
- ⚙ Lever — a bar that pivots on a fulcrum (seesaw, crowbar)
- 🛧 Wheel & Axle — a wheel attached to a rod (car wheel, doorknob)
- 😄 Pulley — a rope over a wheel that changes force direction (flag pole, elevator)
- 🔽 Inclined Plane — a slanted surface that reduces effort needed (ramp, staircase)
- 🔨 Wedge — two inclined planes joined at a point (axe, knife, doorstop)
- 🪝 Screw — an inclined plane wrapped around a cylinder (screw, bolt, spiral staircase)
Key Idea
Simple machines do NOT reduce the total work needed — they change HOW you apply force. A ramp lets you use less force over a greater distance to accomplish the same work.
The Lever
A lever has three parts: the effort (force you apply), the load (weight you're lifting), and the fulcrum (pivot point). The position of the fulcrum changes how easy lifting is.
The lever rule: Effort × Effort Distance = Load × Load Distance
⚙ Virtual Lab: Lever Balance
Drag the fulcrum position slider and change the load weight. Will the lever balance?
Fulcrum position
Load weight
Quick Check
Which simple machine is a ramp?
Moving the fulcrum closer to the load on a lever: