When there are parts of an experiment that scientists cannot carefully control, they should A. change their hypothesis to include all the variables. B. ignore the other variables and record only the important data. C. redesign the experiment to be sure they are testing only one variable. D. try to set up a new experiment that tests a few variables at once.

Question

When there are parts of an experiment that scientists cannot carefully control, they should 	A.	change their hypothesis to include all the variables. 	B.	ignore the other variables and record only the important data. 	C.	redesign the experiment to be sure they are testing only one variable. 	D.	try to set up a new experiment that tests a few variables at once.

blues · Answer

This is a very tough question. In theory, I think the 'correct' answer would probably be C.

In practice this is not always possible. Experimental possibilities and limitations depend on the system being studied. Moreover, organisms, single cells and even single molecules are inherently complex systems and it is incredibly (and often impractically) difficult to understand in mechanistic detail how every little piece affects the part of it you want to study.

People end up doing a balancing act between options A, B and D, with as little of B in the mix as possible.