Question

What is the difference between an observation and an inference?

Answer 1

Observations is something you use with your five senses.
Inference is something you know from you previous knowledge.

Answer 2

when you percieve something or changes in something, with your 5 senses (as said by @studybrains), it means that you are observing the thing
and inference is the conclusion that you make upon the observations and your initial knowledge:)
@studybrains is right