1) Empiricist 2) Tinker 1) Investigator 2) Research worker 3) Researcher 
• (n.) One who makes experiments; one skilled in experiments.
The person who conducts the experiment.
The person who conducts the experiment.
The person who conducts the experiment.
Ex·per'i·men`ter noun One who makes experiments; one skilled in experiments. Faraday. 
[n] - a person who enjoys testing innovative ideas 2. [n] - a research worker who conducts experiments
noun a research worker who conducts experiments