LeverLab
The Journal
How Levers Work: The Three Classes Explained
A lever is a rigid bar and a pivot — nothing more — yet it's the oldest force-multiplying machine we have. Here's the moment-balance math behind it, and how the three classes of lever differ.
Block and Tackle: How Pulleys Multiply Your Pulling Force
A single pulley just changes the direction you pull. Add a second, movable pulley and you start multiplying force — here's how counting rope segments tells you exactly how much.
Gear Ratios Explained: Trading Speed for Torque
Every meshed pair of gears is really a rotating lever, and the tooth-count ratio between them tells you exactly how much speed you're trading for torque, or vice versa.
Why Ramps Make Heavy Loads Easier to Move
An inclined plane doesn't reduce the work needed to lift a load — it spreads that work over a longer distance so the force required at any moment is smaller. Here's the math and the trade-offs.
The Physics of the Screw: From Archimedes to the Modern Bolt
A screw is an inclined plane wrapped around a cylinder, which is why a small turning effort can generate enormous clamping force — and why threads hold their position without slipping.
Archimedes and the Machines That Shaped Engineering
Long before 'mechanical advantage' had a name, Archimedes and later Leonardo da Vinci studied levers, pulleys, and gears closely enough to leave behind ideas engineers still use today.
How to Build a Simple Machines Science Fair Project
A good simple-machines project doesn't need fancy materials — it needs a clear prediction, a way to measure the real result, and an honest comparison between the two. Here's a practical walkthrough.