To make their observations, scientists use their own senses, instruments (such as microscopes) that enhance those senses, and instruments that tap characteristics quite different from what humans can sense (such as magnetic fields).
(instruments; tap; characteristics quite different from what humans can sense (such as magnetic fields) (humans; can sense; ) (To make their observations; use; their own senses)
instruments humans To make their observations
tap can sense use
characteristics quite different from what humans can sense (such as magnetic fields
their own senses