Answer: Hello!
Where are most experiments done?
The answer is a laboratory.
The benefits of this choice are that the laboratory is a controlled environment, where all the variables are controlled (a clean place, the temperature is controlled, the pressure is controlled, etc) and this allows us to have a better description of the phenomena that you are observing. Also having a controlled experiment allows doing the same experiment anywhere in the world, in order to see the repetitively of the experiment when is done in other laboratory and by other scientists.