Experiment Ultrasonic Wave Propagation in Air using EXAO

Topics covered:

- Speed of ultrasonics

- Decrease based on distance

- Relationship between speed, distance, and time

Principles and objectives:

An ultrasonic transmitter emits an ultrasonic wave that faithfully reproduces the electrical voltage applied to its terminals. A receiver transforms the ultrasonic wave into an electrical voltage that faithfully reproduces the ultrasonic wave.

The ultrasonic rangefinder transmitter can emit bursts or periodic waves; in our case, we will use short bursts.

Power the Moduson transmitter with the supplied 12V power supply, place it on the Moduson rail so that the 2 receivers are directly facing the transmitter. The transmitter must be in burst mode with short bursts. The 2 receivers are positioned at an equal distance.

Connect the socket ouExperimentuts of the 2 receivers to the inputs of the oscilloscope or the ExAO console.

Slowly move one of the receivers away from the other, which will remain fixed. Depending on the respective positions of the 2 receivers, a shift between the 2 receptions is easily highlighted.

Using the cursors of the oscilloscope or the pointer of the Scientific Workshop software, determine the delta t between the 2 start of signal receptions for each receiver. Then, this value is used to calculate a speed in the spreadsheet, using the distance separating the 2 receivers.

Move one of the receivers and take a second measurement. It is easily observed that the further apart the 2 receivers are, the greater the difference between the 2 signals.

Calculate the speed of sound by determining the travel time between the 2 receivers and the distance separating the 2 Moduson receivers.

- Ultrasonic speed pack (ref 222010) - Foxy 2 console (ref 485000) - A.S. Sup software (ref 000137)