The Scientific Method

Scientific Method in Thought and Deed

The scientific method consists of five main steps: observation, formation of a question, a hypothetical answer to that question, a prediction of events based on the hypothesis, and finally, a test of that prediction. In this paper, I will outline the process for an experiment concerning plants' response to light, explaining each step of the scientific method. Following that is a brief example of how a friend and I recently used the scientific method to settle a friendly dispute, again in a step-by-step explanation.

The Plant Experiment

Observation:

Plants growing near windows tend to grow towards the window, getting leafier and taller on the side nearer the glass, and sometimes actually leaning towards the window.

Question:

What makes plants behave like this -- that is, grow towards a window as opposed to neutrally or in any other direction?

Hypothesis:

Because plants rely on light for photosynthesis, the process by which they produce their energy, plants respond to and actually reach out for light. It is the light coming through the window that causes the plants growth to be uneven, and that causes the leaning in some cases.

Prediction:

Plants whose light source was specifically limited to one side or another would show significant changes in growth pattern, growing towards the light source both in overall volume of leaves and other matter, as well as the entire plant leaning from the stem towards the light source.

The Experiment (Testing the Hypothesis/Prediction):

To set u this experiment, the ideal set up would be a dark room with an individual darkened compartment for each plant, each with an identical light source differing only in its placement. These compartments would need to be large enough to allow growing room, and be well-ventilated without letting external light through. The interior of the compartments would ideally be black, to minimize reflection from the light source. Each plant would have a unique light source, shining on it from a unique angle -- some from the north, some south, etc. -- to control for any directional growth tendencies plants might have. The plants should all be of the same species, ideally from the same seed batch, and all aspects of plant care aside from light must be exactly the same for every plant. The experiment must control watering levels, soil the and density, and nutrients administered to minimize any effects these influences would have on the results.

Several control plants would also be useful -- one in a darkened compartment with light shining directly down on the plant, perhaps in a more reflective (white) compartment, several with multiple light sources shining from different directions, some grown in a controlled environment outside the compartments entirely, in full ambient light. All other conditions for the control plants (i.e. water, soil, etc.) should be identical to the plants in the experimental group. Lighting periods and cycles should also remain identical for all plants. Results would be measured in weekly or bi-weekly intervals (depending on the growth rate of the plant used) by a leaf count according to hemispheric position -- that is, the plant would be "divided" into two halves, the one facing the light source and the one facing away, and the leaves per half would be counted -- as well as a measurement of the angle of growth as it deviates from the center of the compartment (plants would need to be centered in the soil for this measurement to be accurate, of course).

According to the scientific method, the results of any experiment cannot prove a hypothesis correct. But if it does not prove it incorrect, and the experiment was conducted in a logical and thoughtful way, the hypothesis will be supported by the experimental evidence. I believe that this experiment, if properly conducted, would shed some light on the subject of plant growth.

The Faster Trip: The Scientific Method in Action