Question

if a scientist tells us that two atoms separate from one another, what kind of observation did they make? microscopic macroscopic

Explanation:

Atoms are extremely small particles. Observing them requires specialized instruments as they are not visible to the naked - eye. Microscopic observations deal with objects at the atomic and sub - atomic scale, while macroscopic observations are of objects visible to the unaided eye. Since atoms are not visible to the unaided eye, this is a microscopic observation.

Answer:

Microscopic