If that’s too hard, how many collapses in 100 cc’s of boiling water in one second?
In biology, the very first robin that is scientifically described is preserved and called the “type robin”. The “type robin” for collapse was described by Einstein in 1905, and won him the Nobel prize. It is called the photoelectric effect. (Later collapse was formalized by von Neumann as a mathematical projection.)
A very similar effect is the building up of an Airy circle in a telescope. Another is the point by point emergence of an interference pattern in a two-slit experiment, perhaps very slowly. In these examples, “collapses” can be counted. When one photon is absorbed and detected, one collapse happens. When a second photon is absorbed, a second collapse happens.
The collapse is caused by the photon hitting the detector. (Or the collapse is caused by the silicon atom absorbing the photon.)
Collapses like these are countable and it makes sense to ask and answer how many there are in a given 4-volume of spacetime.
So, how many?