The source of the microscopic animalcules described by Leuwenhoek was pond water. All these small organisms were single celled organisms.
The O in pond has a short O sound, as in bond and fond.
The O in pond has a short O sound as in pot and fond.
pond water
not a sound
pond water
pond water
Sound waves are described as pressure waves because waves produces pressure by which sound is produces
Hertz can be described as how much the sound releases its power.
The word "pond" has a short o sound, like the "ah" in "hot."
"Fond" has a short vowel sound. It is pronounced as "fawnd."
Yes, it makes a sound. A sound does not have to be recorded, by the ear or a recording device, to have happened. Such things are called axiomatic and are self evident. Example: If a blind man throws a pebble into a pond, does the pond ripple?