In order to find the empirical formula of this compound, you must first calculate the ratio of elements.

It is reported that North Korea has conducted another nuclear bomb test.

He is looking for a proving ground to test his new theory.

He conducted a thought experiment to solve a problem in physics.

This is my unused camera.

He admitted that it is difficult to execute the plan, saying 'it is easier said than done.'

Well then, I'm off.

It is reported that North Korea has conducted another underground nuclear test.

He is an expert in experimental psychology.

He is spending a lot of time on experimental research.