experimenter

"The teacher asked, "Who will present the project next week?" "

"The students conducted several experiments in the science lab to test their theory about plant growth. "

"Each person is unique, both mentally and physically."

"His parents got him an in with the company."

"He listened carefully to his mother's concerns, feeling sorrowful about her disappointment. "

"It looks weaker and weaker, the more I think about it."

"My science teacher took the class to the lab to perform experiments. "

"The science experiment involved mixing several chemicals together to see what would happen. "

"Mix the eggs and milk with the flour until the consistency is smooth."

"The children asked their teacher for help with those math problems; she explained them. "

"Before dinner, I finished my homework. "

"We measured the temperature with a thermometer.   You should measure the angle with a spirit level."