I can build and analyze a gear train that changes speed, torque, or direction of rotation.
POE Unit 1 • Lesson 1.4
Gears and Drive Ratios
Focus question: How do gear ratios change speed, torque, and direction in a mechanical system?
Mission Briefing
Today’s Plan
A focused lesson sequence that builds toward the VEX Rover Mechanisms Challenge.
Opening promptConcept voteAerospace linkCompare optionsEvidence challengeQuick checkExit ticket
Lesson Targets
What You Will Be Able to Do
Gear ratio investigation table
The gear analysis correctly predicts ratio, output speed, torque trend, and rotation direction.
Activity Flow
How the Lesson Moves
This page highlights the lesson elements you need for practice, evidence, and submission.
1. Build or inspect a gear pair
Identify the driver, driven gear, tooth counts, and contact direction.
2. Calculate the ratio
Use tooth counts to predict output speed and torque change.
3. Verify motion
Compare the prediction with an observed or simulated gear train.
Lesson Interactive
Explore Gear Ratio, Speed, and Torque
Adjust tooth counts and input speed. The dashboard predicts ideal output behavior for one external gear pair.
Gear Inputs
External gears reverse direction at every mesh.
Predicted Output
Ratio
Output speed
Ideal torque factor
Select the performance trend
Adjust the ratio, select the matching performance trend, and check your prediction.
Today’s Work
Main Deliverable
Gear Ratio Investigation Table
Compare at least two gear pairings for a rover mechanism.
- Record driver and driven tooth counts, ratio, output speed, torque trend, and direction.
- Recommend one pairing for either speed or lifting torque and defend the choice.
Exit Ticket
Mission Debrief
One way today’s lesson connects to an aerospace mechanism or VEX rover system.
One type of evidence you could use to support a design decision.
One question you still have about mechanisms, energy, power, or the Unit 1 challenge.
Resources
Lesson Resources
Principles of Engineering
Return to the POE course hub for units, resources, certifications, and current course information.
VEX Rover Mechanisms Challenge
Use this unit project context when connecting the lesson to mechanism planning, testing, and design review evidence.