[PHI 3800] Looks can be deceiving

According to Constructive Empiricism:

science aims at truth about observable aspects of the world, but that science does not aim at truth about unobservable aspects. Acceptance of a theory, according to constructive empiricism, correspondingly differs from acceptance of a theory on the scientific realist view: the constructive empiricist holds that as far as belief is concerned, acceptance of a scientific theory involves only the belief that the theory is empirically adequate.

According to van Fraassen:

X is observable if there are circumstances which are such that, if X is present to us under those circumstances, then we observe it.

For the constructive empiricist, then, microscopic objects and processes that are too small for us to see with the naked eye, such as cells and intracellular process, are unobservable.

Now, instead of the too small, consider the too slow. We cannot observe with the naked eye the growth of plants, for example, not because plants are too small, but because plant growth is a process that occurs too slowly for us to notice. To observe the growth of plants, we need to use technology. In particular, time-lapse photography allows us to capture processes that occur too slowly for us to observe with the naked eye.

For the constructive empiricist, then, are slow processes that we cannot observe with the naked eye unobservable?

Similarly, consider the too fast. We cannot observe with the naked eye the bouncing of raindrops off puddles, for example, not because raindrops are too small, but because this is a process that occurs too fast for us to notice. To observe the bouncing of raindrops off puddles, we need to use technology. In particular, high-speed photography allows us to capture processes that occur too fast for us to observe with the naked eye.

For the constructive empiricist, then, are fast processes that we cannot observe with the naked eye unobservable?