according to

Speed = distance/time

Prepare a 100m-long water pipe that can run water, a sound generator (preferably sounding at regular intervals), a receiver and a timer (stopwatch and mobile phone are basically enough).

The sound generator sounds at one side of the water pipe and the receiver receives it at the other side. If it can't be collected, you can shorten the water pipe.

Vocal regularity, not 1s once (to eliminate interference, the time interval can be appropriately extended), about 30 times,

Because the received sound should spread through air, water pipe and water, the speed should be faster than that of air; Water pipe > water, don't use the first two sounds. Time starts at the third sound and ends at the last sound. At this time, the whole distance through which sound passes should be1100mm.

X

30 times =3000m, the time should be

The recording time-the interval between 30 times, according to the propagation degree of sound speed in seawater, is about 1500m per second, and the obtained time should be more than 2s. If you can get such time, I think your experiment should be basically successful. If the obtained time deviates too much from this time, the experiment will fail. Hmm. How interesting

Good luck!