The goal of science is to investigate and understand nature, to explain events in nature, and to use those explanations to make useful predictions. The same is true for oceanography. Oceanography is a branch of earth science, and in a quest to study the earth, scientists investigate the earth’s oceans to make useful predictions. You should already be familiar with the scientific method, but we will review the scientific method just in case.
Scientific Method
There is no one “scientific method.” Scientists may perform their research differently based on the scope and topic of study. Some researchers observe, describe and report on some subjects and leave it to others to hypothesize. Others develop hypothesis, perform experiments and share their findings for others to use. However, there is a basic format for approaching a problem and finding a solution in a logical manner. The main steps of the scientific method include:
- Identify a problem
- Gather information
- Make a hypothesis
- Test the hypothesis
- Analyze the results
- Draw conclusions
- Communicate results
Identification of a problem is the primary step of the scientific method. Scientists have something that they are interested in studying and come up with a specific question that they are interested in finding the answer to.
Next, scientists gather background information on the topic to help make an educated guess as to what the answer may be. This educated guess is the hypothesis.
They then perform an experiment to see if the experiment produces the hypothesized results. By studying the results, the scientist can come to a conclusion and share it for others to study, retest or interpret.
It is important to understand that nothing is ever proved absolutely true by the scientific method. Hypotheses are supported or refuted, based on the data gathered. Theories are developed when patterns of hypotheses emerge. If one or more of the experimental relationships hold, the hypothesis is considered a theory. Scientific laws are evolved from theories which explain events in nature that occur consistently and yield identical results. The law of gravity is an example of a scientific law.
Observations
Observations involve all five of our senses. We make observations using our sense of sight, smell, taste, hearing, and touch. The information we gather from our senses is called data. There are two types of observations.
Quantitative observations are observations that detail the quantity or numbers associated with an observation. Example: “There was a temperature increase in the water of 10ºC.”
Qualitative observations are observations that detail the quality of an object such as size, shape, smell, sound, etc. There are no numbers associated with qualitative observations. Example: “The water was very still.”
After we make observations, we tend to attach a primary explanation to the observations. The explanation typically has a logical connection to the data and is based on prior experiences. This suggested explanation is called an inference.
Experimental Design
Because scientist may perform their research differently, experimental design often varies as well. There are however, things that remain common in most scientific experiments.
Hypotheses may be developed based on prior knowledge, inferences, or just plain guesses. Yet, a hypothesis is only useful if it can be tested.
Experiments also involve variables and constants. Variables are the things that change in the experiment, whereas, constants are the things that stay the same. The constant is sometimes called the control. When scientists use a control, they are using it to compare against the experimental results. This is called a controlled experiment. Not all experiments are controlled experiments. There are some tests that scientists perform that do not require the use of a control for a comparison.
There are two types of variables. If the variable is deliberately changed by the scientist in order to test the result, the variable is called the independent or manipulated variable. The result of this change is also a variable. It is called the dependent or responding variable.
To help you better understand this information we will review a simple oceanography experiment.
A student is interesting in studying how currents move in relation to temperature. The student adds food coloring to ice water and uses a dropper to add the ice water to three separate beakers of water. The first beaker contains cold water, the second contains room temperature water and the final beaker contains warm water. The student observes that the colored ice water sank to the bottom of the beaker that contained the warm water, but remained at the top of the beaker with the cold water.
See if you can answer the following questions based on the student’s experiment:
Was this a controlled experiment? If so, what was the control? What were the variables?
The student’s experiment was a controlled experiment and the room temperature water served as the control. The independent or manipulated variable was the cold water that was added to the three beakers. This was the factor of the experiment that the student controlled. The dependent or responding variable was the movement of the water based on the temperature. This is what the student observed as a response to the independent variable.
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