A LEGO simple machine project lets you build a working model that moves, lifts, and changes force using everyday classroom pieces. In one tabletop machine, a lever can push or pull, gears can transfer turning motion, and a pulley can lift a small load. This project matters because it shows how real tools and machines make work easier.
It also helps you practice planning, measuring, testing, and improving a design.
Key Facts
- Work = force × distance, so W = Fd.
- A lever turns around a fixed point called a fulcrum.
- Mechanical advantage = output force ÷ input force.
- For gears, gear ratio = teeth on driven gear ÷ teeth on driver gear.
- A fixed pulley changes the direction of a force, but a movable pulley can reduce the force needed to lift a load.
- Simple machines trade force for distance, so less force usually means moving the input farther.
Vocabulary
- Lever
- A lever is a rigid bar that turns around a fulcrum to move or lift a load.
- Fulcrum
- A fulcrum is the fixed point where a lever pivots.
- Gear
- A gear is a wheel with teeth that meshes with another gear to transfer turning motion.
- Pulley
- A pulley is a wheel with a groove that guides a string or belt to lift or move a load.
- Mechanical Advantage
- Mechanical advantage is how much a machine multiplies your input force.
Common Mistakes to Avoid
- Putting the fulcrum too close to the effort end, which makes the lever harder to use because the effort arm becomes too short.
- Meshing gears too tightly, which is wrong because extra friction can stop the gear train from spinning smoothly.
- Using a loose string on the pulley, which is wrong because the string can slip and fail to lift the load evenly.
- Testing only once, which is wrong because a simple machine may need several trials to find weak spots and improve the design.
Practice Questions
- 1 A lever lifts a 12 N load when you push down with 4 N of force. What is the mechanical advantage of the lever?
- 2 A 12-tooth driver gear turns a 36-tooth driven gear. What is the gear ratio, and will the driven gear turn faster or slower than the driver gear?
- 3 You build a LEGO machine with a lever, gears, and a pulley, but the load does not rise. Explain two design changes you could try and why each change might help.