The Scientific Method


To understand what the scientific method is and be able to apply it to answer questions.


Anyone who is inquisitive can be a scientist. Scientists answer questions by following a simple, logical, and straightforward prescription which is called the scientific method.

This learning module will provide background for understanding why we were motivated to study the Puna Ridge, what science questions we are seeking to answer, and how we are planning to answer our questions.

This module employs links to DOE E-school Course SA45 for describing the controlled experimental scientific method and for the 2nd learning activity,  and links to learn about the theory of plate tectonics.

Lesson Plan

1. What is science, and how does science work?

Science is about understanding how the Universe works, and in discovering the fundamental reasons why everything works the way it works. 

Why does the deep ocean appear to be darker blue in color than the coastal waters?

Why are some lavas that erupt smooth and flat, and others are round and pillow-like?

Science is

  • objective; its laws and predictions are repeatable and unaffected by human preferences.
  • empirical; its findings are measurable and every theory can be tested.
  • dynamic; the process of scientific investigation leads to new discoveries every day.
  • complex, yet simple; complicated science questions can be broken down into simpler problems, solved, and all the answers woven back together to solve the complex problem.

There are many branches of science that specialize in studying different natural phenomena. For example, scientists who are physicists investigate energy (e.g., motion, heat, light, electricity) and matter, the basic building block of everything, chemists study the basic substances or elements found in the Universe and try to understand how the more complex substances called compounds are formed, biologists study the growth and evolution of plants and animals, and meteorologists study the Earth's atmosphere and its effect on the weather. One of the most important branches of science is mathematics, the study of numbers, shapes, and quantities, because it enables scientists to make measurements, to calculate predictions, and to understand the results of their experiments.

2. Are you a scientist? Some attributes of scientists

Everyone who asks a question or wonders why something happens is acting as a scientist. Scientists are curious people who are always wanting to know about the things around them and why things occur the way they do. Scientists seek to answer questions by following a simple, logical, and straightforward prescription which we call the scientific method. Scientists observe the world around them and produce explanations of why an event occurs. Their explanation, or hypothesis, is then tested, and refined until it is always true so that it can become a scientific law.

Examples of physical scientific laws are Newton's Second Law of Motion (F=ma, force equals mass times acceleration), which describes the speed and position of an object at any instant, and the Law of Universal Gravitation, which states that every object attracts every other object with a force directly proportional to the product of their masses and inversely proportional to the square of the distance between them (F=Gm1m2/R2).

Scientists also come up with ways of doing things better; they design and make machines, like these computers, to make our lives easier, more comfortable, and enjoyable. They may work indoors in laboratories, or outside in the field. They do experiments or scientific tests to examine which variables are most sensitive to changes and to test ideas, and they analyze their experimental results to solve the problem and find out what causes the action. They observe, think, discuss, measure, calculate, and experiment.

Shown below are scientists at work. Left top: Mapping the rift zone. Left bottom: Checking remote monitoring equipment on Kilauea. Right top: Analyzing chemical composition of rocks using an ion microprobe in the lab. Right bottom: Students installing portable seismograph in Kilauea caldera. Photos by Laura Kong.

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What does a scientist do?

Scientists make measurements and collect data, which is often displayed on graphs or charts to assist scientists in understanding their results. The data can be in the form of numbers (such as how much rain fell every day), or descriptions (such as sunny, cloudy, drizzling, pouring rain). Often, data are summarized by plotting a graph which shows how one quantity varies in relation to another quantity. For example, the graph below shows how rainfall on the Big Island compares to Oahu monthly.

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Our analysis of the annual rainfall patterns would tell us it rains more than twice as much on the Big Island as it does on Oahu, and that on average the rainiest months have been November and March.

3. What is the scientific method?

Scientists know that everything behaves according to certain rules or scientific principles. Scientists try to find patterns in things and look for explanations for the patterns. The process by which a scientist finds an explanation to an event is called the scientific method. It is a way of approaching and solving a problem, or answering a question, that is logical and straightforward and can be applied to both everyday situations and specialized research topics. Here's the recipe:

  • ASK a question, or POSE a problem you want to solve.
  • GATHER information about the question.
  • FORM a hypothesis, PROPOSE a solution.
  • DEVELOP methods to TEST hypothesis by making MODEL PREDICTIONS
  • CONDUCT the experiment, or TEST the proposed solution
  • EVALUATE the data -- Is the hypothesis correct? Did it work?
  • REPORT results -- Let everyone who's interested know what you found.
  • AMEND/CHANGE the hypothesis, or PROPOSE a better solution, and try again.

When an experiment is conducted to obtain data to test the model predictions and confirm the hypothesis, it can be a field test or a controlled experiment. By "field", we mean that the data that are collected are taken in the real world, where variations in the natural elements might occur. Earth scientists are generally field scientists, who sample discretely by taking a representative selection of measurements adequate for answering the scientific question that was posed.

Shown below are scientists walking away from an advancing a'a flow which has become too hot to tolerate; and scientist sampling hot lava from Pu'u O'o eruption.

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This is in contrast to the experiments of physicists, chemists, or psychologists, who conduct controlled experiments that allow them to investigate the effects of different parameters by varying each parameter separately while holding all other factors constant.

4. What is Earth science? Why study the Earth? What do Earth Scientists do?

geospace.jpg (12661 bytes)Earth science is all about studying the Earth, all aspects of it, from the atmosphere and the oceans to the formation of rocks and the eruptions of volcanoes, and all the interrelationships between them, living things, and the environment.

Earth scientists are geologists who study the Earth's history, structure, and composition, meteorologists who study atmospheric processes that generate weather, geographers who study the Earth's surface, oceanographers who study the water chemistry, currents, and marine life in the oceans, and ecologists who study the interactions within ecosystems.

Understanding  how the Earth works is important because, for example, this is how we know where to look for valuable mineral and energy reserves, where we should find our drinking water, and where and when floods, hurricanes, and severe winter storms are going to occur. Understanding how living organisms interact and impact their surroundings increases our awareness of how today's polluting industries and agricultural pesticides can potentially wipe out our Earth's precious and limited natural resources.

SM4_CoastalEntry_3aug98.jpg (14300 bytes)On the Big Island, geologists are studying the gas emissions from the 15-year old Pu'u O'o eruption of Kilauea. They are also working with local health professionals and officials to better understand the damaging effects that volcanic air pollution (vog and acid rain) has had on respiratory health, safety of drinking water from rainwater-catchment systems, and leafy agricultural crops susceptible to chemical leaf burn.

Picture shows geology class observing the coastal lava entry in August, 1998. During that visit, the class observed a small collapse of the lava bench into the ocean. Photo by Laura Kong

More than 70% of the Earth's surface is covered by water, making the study of oceans and geological oceanography (the geology beneath the oceans) an important component of the earth sciences. The Puna Ridge expedition explores the undersea world of a volcanic rift zone, where lava has erupted to form a long underwater mountain range that connects the submarine feature to Kilauea Volcano's East Rift Zone on land. In addition to the Puna Ridge web site, the DOE Electronic School is sponsoring a Seminar in Scientific Research: Year of the Ocean, which will provide exciting research opportunities on ocean-related topics.

What do Earth Scientists do? A Geologist's Scientific Method

A geologist's laboratory is the planet Earth, and so it is impossible to test one's ideas using a controlled laboratory experiment. Instead, geologists collect data by mapping and then testing their theories on the real world. If we're trying to understand beach erosion, we would:

Make field observations at a number of locations where beaches are disappearing.

Identify similar physical conditions among all the locations that are being eroded.

Construct a model describing important causative factors and how each contributes to the end beach erosion. Your model might say that erosion is greatest in places where man has built seawalls because they think it will prevent the sand from eroding.

Make predictions based on the model. Your prediction would be that beaches with seawalls are more eroded (or smaller) than beaches without seawalls.

Test the predictions in the field by designing an experiment to collect the right type of data to answer the questions. The data that you want to collect is the size of the beach in places where there are seawalls and where there aren't. You should do the comparison in places where the ocean and wind conditions are similar, e.g., adjacent houses with one having a wall and one with no wall, because we want to minimize any variation in the other physical variables that could affect beach erosion. Finally, we also will want to obtain data over a number of different time periods, say monthly or yearly, so that when we average the results the answer is relatively insensitive to minor transient weather or man-made fluctuations. 

A scientific theory that has finally been accepted has gone through many iterations of model construction and prediction, followed by data collection and model refinement, until all aspects of the theory are repeatable.

Meet A Scientist

Here's what a couple of real-life scientists say about what they do and why they enjoy doing science.

sm4_df4.jpg (13890 bytes)Dr. Richard Fiske, Smithsonian Institution

What do you do?

I study submarine volcanoes near Japan and the active volcano, Kilauea, in Hawaii. The Japanese work involves the use of a 3-man research submersible that takes me and two pilots into a large volcano crater on the sea floor. This crater, now about 1400 m deep, was the site of a huge under-water eruption so strong that it may have broken through the sea surface and rose into the air. It would not be very healthy to be in a boat near such an eruption! One extra thing: Japanese scientists have recently discovered a large deposit of minerals near hot-water vents on the floor of the crater. This deposit contains much gold, silver, and other metals, and may someday be mined.

In Hawaii, I and scientists from the Hawaiian Volcano Observatory are studying the history of explosive eruptions at the volcano and the evidence, contained in rocks and ash deposits, of motion of the entire south flank of the volcano toward the sea. This work involves field studies and the use of surveying instruments to measure the motion of parts of the volcano (see his picture taken on Kilauea while he was doing field work).

Do you enjoy what you do?

What's not to enjoy? I get to visit exciting volcanoes, both on land and on the ocean floor. I get to be involved in scientific projects that are interesting intellectually and important to society. I get to work with excellent scientists from this country and abroad. It's a good life!


Dr. Judith E. McDowell, Woods Hole Oceanographic Institution

What do you do?

I am interested in how environmental variables affect the development and reproduction of marine animals. My work is particularly focused on populations of marine bivalve molluscs and how they adapt to changes in their habitats. Populations of bivalve molluscs comprise an important ecological and economic resource in coastal and estuarine habitats. Variations in reproductive output and population dynamics of bivalve molluscs are highly sensitive to environmental perturbations. Understanding the interactive effects of natural stressors such as disease or predation, and anthropogenic stressors such as habitat alteration or contaminant exposure may lead to new insights on the adaptive mechanisms employed by coastal shellfish populations in coping with multiple stressors in their environment. My work has taken me around the world in comparing bivalve populations from polar to tropical seas.

Do you enjoy what you do?

I can’t imagine doing anything else! The work is challenging but very rewarding and the results of my work have been directly applied to management decisions in coastal areas from around the world.


5. How will we use the scientific method to study the Puna Ridge?

SM5_puna_3d.jpg (12178 bytes)Our research expedition to the Puna Ridge will take us to the seafloor to investigate volcanic and tectonic processes along a volcanic rift zone. Geologists and geophysicists, graduate students, and high school teachers will be on board sharing in the excitement of scientific discovery as we "see" the first detailed sonar and photographic data ever collected from this area of the seafloor.

What motivates us to study the Puna Ridge? What science questions do we want to answer? And, how we are planning to answer our questions? Check out about the cruise.

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1. Learn about the theory of plate tectonics

Describe how the development of plate tectonics follows the scientific method.

2. Design a controlled scientific experiment.

3. What are the similarities and differences between the scientific methods described in Activities 1 and 2?


Ardley, N., Dictionary of Science, Dorling Kindersley Limited, London, 192 pp., 1994.

Farndon, J., Dictionary of the Earth, Dorling Kindersley, London, 192 pp., 1992.

Kramer, S. P., How to Think Like a Scientist, Thomas Crowell, New York, 44 pp., 1987.

Limburg, P. R., Oceanographic Institutions, Elsevier/Nelson Books, New York, 265 pp., 1979.

Tobias, S., Can C. T. Tomizuka, Breaking the Science Barrier, How to Explore and Understand the Sciences, College Entrance Examination Board, New York, 163 pp., 1992.