What elements such as variables, hypothesis, etc. are used in an experiment?
The actual objects or substances used in an experiment will vary, depending on what it is the experiment is testing. However, all well-designed experiments have some common elements.
The beginning point of an experiment comes from the observation that has been made and the question that arises as a result of that observation - something that needs to be investigated for explanation or further understanding. The hypothesis is a potential answer to that question; the experiment is designed to test the correctness of that hypothesis.
Experiments use a control sample and experimental samples to conduct the testing. The control sample is given "normal" treatment, while the experimental samples are treated with variables - changes in conditions, carefully documented - that allow the experimenter to evaluate the effects, if any, of those changes.
Documentation is important for any experiment, as it records the conditions created and the results observed after administering those variable treatments to the control and experimental samples. At the conclusion of the experiment, analysis of the results demonstrated allow the experimenter to reach a conclusion, determining that the hypothesis has been supported or disproved.