Wide World of Gears
Gears are commonly found in wristwatches. Students working with robotic racer (right).Copyright (left) Wikimedia Commons; (right) 2010 Polytechnic Institute of NYU
In an interactive and game-like manner, students learn about the mechanical advantage that is offered by gears. By virtue of the activity's mechatronics presentation, students learn to study a mechanical system as a dynamic system under their control as opposed to a static image. The system presented is of two motorized racing cars built using the LEGO® MINDSTORMS® robotics platform. The altered variable between the two systems is the gear train; one is geared up for speed and the other is geared down for torque. Students collect and analyze data to reinforce particular aspects and effects of mechanical advantage.
The modification to mechanical systems offered by gears is an advanced example of simple machines. Mechanical engineers design gear systems for machines of all forms for industry and everyday life. Gears may be used in various configurations ranging from very simple (binary set-up) to very complex (compound gear pairs). Gears are seen in many different devices, such as mechanical watches/chronographs, film cameras and automobiles. The study of gear systems is often neglected in K-6 education due to its complexity; however, this exercise in racing robots aims to simplify a central concept for many mechanical engineers, the "big impact" effects of using gears in two different configurations.
After this activity, students should be able to:
- Collect, average and compare single variable datasets.
- Compute speed from distance and time measurements.
- Clearly and confidently explain that gears can be used together in different sizes.
- Predict what would occur if gears were added to a system in either gearing-up or gearing-down configurations.