Simple Machine Crane

Name of Activity

Simple Machine Crane


Matt Mueller, Emily Naito, Mary McCormick, Karman Chu


Simple machines, pulleys, gears


LEGO Building

Grade Level



3 Hours Total

Brief Description

Students design and build a crane system using simple machines that will lift as much weight from the floor as possible. The simple machine system will be attached to a motor on the desk. Students may use string attached to motor, gears, pulleys to lift the weights.

Lesson Objectives:

Designing and building simple machine systems, using pulleys and gears in combination, employing engineering design process to design, build, and test systems.

Materials Needed:

LEGO bricks, gears, pulley wheels, string, motors, weights, cup for weights.

Preparation and Set Up:

Strings attached to cups that can hold weights, worksheets for students to learn about gears and pulleys.

Necessary Background

Simply machines background on gears, pulleys functions and uses.


1. Clarify the problem: lifting as much weight as possible from the floor to the desk using simple machines – gears and pulleys – that are attached to a motor on the desk. 2. Talk about how it might work.  What do gears do? What do pulleys do? 3. Brainstorm designs in groups. 4. Get materials and start building. 5. After 1 class period, review gears and pulley functions and uses.  Work more on designs. 6. Return to building, testing and revising as needed. 7. Come together as a class to talk about different designs.  Test how much weight each design can hold, and make it collaborative by seeing how much the whole class holds together (summation of weights). 8.  Discuss as group how the designs worked. 9. Redesign – If time, let students incorporate what they lave learned to redesign.


Class discussions:

How might these cranes be more effective with other simple machines? How do cranes work in real life? Where do we see cranes?

Redesign could be to make it more challenging by lifting weight faster/slower.

Reference 1

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