First Gear

What are gears?


Gears transmit motion. They’re linked together by their teeth. One gear wheel drives another, which in turn may be used to drive another.

What happens to the turning direction when two gears are meshed together?

Build this *Gear Model*.


It’ll help you explore the basics of gears.

Do a test run.

EV3 Classroom-Programs 2-2-program en-us

Place the model on a solid and level surface. Make sure that both the gear pointer and the reference motor pointer point upwards. Run the program and keep track of the gear pointer to count the number of rotations. Make sure to observe its turning direction.

Does the reference motor complete one rotation and do both motors stop turning at the same time?

Record your results.


Record the experiment number, whether it’s geared up or down, the gear ratio, your prediction of what’ll happen, the number of rotations observed, and turning direction in a testing table. Make sure to leave enough space to record other observations.

Perform the experiment using the default gearing, and repeat the experiment for each of the other gearing options shown in the “Hint” below.

Changing Gears

This is the default gearing, which you’ll have to remove:


Build the second gearing using a large and a small gear:


Build the third gearing using the same gears:


Finally, build the fourth gearing using three gears, including an idler gear:


Summarize your results.


Use your measurements for each gearing option to analyze how the gearing relates to the turning direction and number of rotations of the gear pointer.

How well did your predictions match your observations of the turning direction and turning speed? Did anything surprise you?

How did you do?


What did you do well? Is there anything you could’ve done better?

Excellent, now you have a basic knowledge of simple gear configurations. Let’s gear up for the next lesson!