|Level: Advanced||Duration: NA|
|Grade Level:||Author: LEGO Education|
|Topics: measurement, sound|
|Materials: LEGO MINDSTORMS Education NXT Base Set, LEGO MINDSTORMS Education NXT Software 2.1|
Students measure the sound levels of applause using a meter that gauges decibels.
How do you tell performers you liked a show? With applause! Could you tell if an audience liked one performer better than another based on how loud the applause is? Invent an RCX applause meter to measure an audience’s reaction to a performance of some kind. Be sure to include a moving part that goes faster if the audience claps more loudly.
- As a class, build an applause meter that includes a moving part that goes faster if the audience claps more loudly.
- Write a program in ROBOLAB to measure the noise level.
- Upload the program. The data will be calibrated in decibels (dB), which is the unit of measurement for sound.
- Hold a mini talent show or other performance in class that incorporates multiple instances of applause. Let students measure the applause levels at this time.
- Download the acquired data to the computer.
- Examine the data. Identify where the applause was loud, where it was soft, and where the audience was silent.
Ask students to record the results of their applause meter. Some questions they should answer include:
- How well did your applause meter work?
- In this activity, you represented the sound data in two ways, by the speed of your moving applause meter and by a plot on the graph. What are the advantages and disadvantages of each method?
- If you had more time, how would you improve your applause meter?
Test how well your applause meter works. Attach a rotation sensor to it. Modify the data-logging program by logging the rotation sensor on Port 3, in addition to the sound sensor on Port 1. Run the program and upload the data. To find the rotation speed, use Compute Tools 3 to take the derivative (d/dt) of the raw rotation sensor data. Use Compare to compare the sound readings and rotation speed. Do the peaks and valleys correspond?