what are the assumptions made by scientists to stady how things work
Answers
1- Uniformity, which is that the laws of nature are constant through time and space. This includes the assumption that two scientists conducting the exact same experiment should get the exact same results.
2- Empiricism, which is that the forces and processes of nature deal with tangible matter and energy only. Things that can be measured. This disqualifies any supernatural explanations -- not because they are necessarily false, but because they cannot be measured or controlled in any way.
3- Causation,which holds that all events have a cause that can be determined.
There are probably others that could be thought up, but the point is that science relies on a few assumptions that in themselves cannot technically be proven, but they are accepted because the scientific method could not be effective without them.