A student wants to shorten the ripening time for tomato plants. He predicts that the more water the plants receive,the faster they will ripen. To test this prediction,he grows 20 tomato plants in a garden in full sunlight that has dry soil and 20 tomato plants in a garden with a shadier location where there is greater moisture content in the soil. He then records the time it takes for fruit to develop and ripen on the plants in each garden location. State a serious error the student made with the design of the experiment. State all the constants in the problem.

The major problem with this experiment is that he should have had a constant variable (in the form of the surrounding temperature) for his groups. Meaning, he should have had both groups planted in full sunlight and/or a shadier location since his prediction was on water intake by the plant and not the surrounding temperature.

The independent variable here is the type of soil (moist and dry) used while the dependent variable here is the time it took the fruit to develop and ripen on the plants in each garden location.

NOTE:

Independent variable can be described as the variable that is not dependent on any variable in the course of an experiment. It is also changed by the researcher during the course of the experiment.

Dependent variable can be described as the variable that is been tested during the course of the experiment.