* Formal method of study: This implies a structured approach with defined steps and procedures.

* Control and experimental groups: This is a key element of experiments. The control group serves as a baseline for comparison, while the experimental group receives the treatment (in this case, infrared light).

* Determining whether plants grew faster or slower: This is the objective of the experiment – to test the effect of infrared light on plant growth.

Therefore, the student is not simply observing plants; they are actively testing a hypothesis using a controlled scientific method.