Lifter Phenomenon & Experiment: Measuring Thrust from Ions
Figure 1. A 3D model of the activity experimental setup.Copyright 2009 Washington State University
Student teams each assemble a wing component of a lifter with the goal to test the lifter wing and measure the force exerted when high voltage is applied to it. After an introduction to torque and its use to measure force, students calculate the change in the torque when a high voltage is applied to the wing portion of the lifter using a fulcrum. Once a group has assembled its wing portion, the teacher tests it with a high-voltage power supply, marking the change in the balance so that students can calculate the force. Then groups adjust the gap between the electrodes and re-measure the force. Groups each repeat this process three times, which enables students to estimate the magnitude of the force as a function of the gap between the electrodes. This experiment gives students a chance to explore a fascinating physical phenomena that has, as of yet, not found a real-world application. They conclude the activity by brainstorming possible applications of this technology to solve real-world problems.
This project introduces students to two key engineering concepts. The first is systematic measurement, which is a key aspect of experimentation and hypothesis testing. Once systematic measurements are made, students evaluate their data and think about extreme cases. Next, students are engaged in a novel phenomenon that has no apparent use, but may have new applications in the future. Engineers often explore new ideas before practical applications are known—this is one component of R&D (research and development). After making measurements on the lifter wing, students think of possible uses for this technology.
After this activity, students should be able to:
- Give a basic explanation how the thrust is produced if the only thrust is from ions.
- Detail what measurements were made and why.
- Comment on applications of and precautions when working with high voltage.
- Describe applications of the engineering design process.