READ: What is Science?

1. Nature of Science

Does the word science make you think of high-tech labs and researchers in white coats like the ones in this picture? This is often an accurate image of science but not always. If you look up science in a dictionary, you would find that it comes from a Latin word that means “having knowledge.” However, this isn’t an adequate definition either.

Science is more about gaining knowledge than it is about simply having knowledge. Science is a way of learning about the natural world that is based on evidence and logic. In other words, science is a process, not just a body of facts. Through the process of science, our knowledge of the world advances.

CK-12 Foundation, Physical Science. http://creativecommons.org/licenses/by-nc-sa/3.0/

2. The Goal of Science

Scientists may focus on very different aspects of the natural world. For example, some scientists focus on the world of tiny objects, such as atoms and molecules. Other scientists devote their attention to huge objects, such as the sun and other stars. But all scientists have at least one thing in common. They want to understand how and why things happen. Achieving this understanding is the goal of science.

Have you ever experienced the thrill of an exciting fireworks show like the one pictured in the Figure below? Fireworks show how the goal of science leads to discovery. Fireworks were invented at least 2000 years ago in China, but explaining how and why they work didn’t happen until much later. It wasn’t until scientists had learned about elements and chemical reactions that they could explain what caused fireworks to create brilliant bursts of light and deep rumbling booms.

3. How Science Advances

Sometimes learning about science is frustrating because scientific knowledge is always changing. But that’s also what makes science exciting. Occasionally, science moves forward in giant steps. More commonly, however, science advances in baby steps.

Giant steps in science may occur if a scientist introduces a major new idea. For example, in 1666, Isaac Newton introduced the idea that gravity is universal. People had long known that things fall to the ground because they are attracted by Earth. But Newton proposed that everything in the universe exerts a force of attraction on everything else. This idea is known as Newton’s law of universal gravitation.

Q: How do you think Newton’s law of universal gravitation might have influenced the advancement of science?

A: Newton’s law allowed scientists to understand many different phenomena. It explains not only why things always fall down toward the ground or roll downhill. It also explains the motion of many other objects. For example, it explains why planets orbit the sun. The idea of universal gravity even helped scientists discover the planets Neptune and Pluto.

Baby steps in science occur as small bits of evidence gradually accumulate. The accumulating evidence lets scientists refine and expand on earlier ideas. For example, the scientific idea of the atom was introduced in the early 1800s. But scientists came to understand the structure of the atom only as evidence accumulated over the next two centuries. Their understanding of atomic structure continues to expand today.

The advancement of science is sometimes a very bumpy road. New knowledge and ideas aren’t always accepted at first, and scientists may be mocked for their ideas. The idea that Earth’s continents drift on the planet’s surface is a good example. This idea was first proposed by a scientist named Alfred Wegener in the early 1900s. Wegener also proposed that all of the present continents had once formed one supercontinent, which he named Pangaea. You can see a sketch of Pangaea in Figure below. Other scientists not only rejected Wegener’s ideas, but ridiculed Wegener for even suggesting them. It wasn’t until the 1950s that enough evidence had accumulated for scientists to realize that Wegener had been right. Unfortunately, Wegener did not live long enough to see his ideas accepted.

Q: What types of evidence might support Wegener’s ideas?

A: Several types of evidence support Wegener’s ideas. For example, similar fossils and rock formations have been found on continents that are now separated by oceans. It is also now known that Earth’s crust consists of rigid plates that slide over molten rock below them. This explains how continents can drift. Even the shapes of today’s continents show how they once fit together, like pieces of a giant jigsaw puzzle.

CK-12 Foundation, Physical Science. http://creativecommons.org/licenses/by-nc-sa/3.0/

4. Science as a Process

Chances are you've heard of the scientific method. But what exactly is the scientific method?

Is it a precise and exact way that all science must be done? Or is it a series of steps that most scientists generally follow, but may be modified for the benefit of an individual investigation?

The Scientific Method

There are basic methods of gaining knowledge that are common to all of science. At the heart of science is the scientific investigation, which is done by following the scientific method . A scientific investigation is a plan for asking questions and testing possible answers. It generally follows the steps listed in Figure below . 

Steps of a Scientific Investigation. A scientific investigation typically has these steps. Scientists often develop their own steps they follow in a scientific investigation. Shown here is a simplification of how a scientific investigation is done.

Making Observations

A scientific investigation typically begins with observations. You make observations all the time. Let’s say you take a walk in the woods and observe a moth, like the one in Figure below , resting on a tree trunk. You notice that the moth has spots on its wings that look like eyes. You think the eye spots make the moth look like the face of an owl.

Does this moth remind you of an owl?

Asking a Question

Observations often lead to questions. For example, you might ask yourself why the moth has eye spots that make it look like an owl’s face. What reason might there be for this observation?

Forming a Hypothesis

The next step in a scientific investigation is forming a hypothesis. A hypothesis is a possible answer to a scientific question, but it isn’t just any answer. A hypothesis must be based on scientific knowledge, and it must be logical. A hypothesis also must be falsifiable. In other words, it must be possible to make observations that would disprove the hypothesis if it really is false. Assume you know that some birds eat moths and that owls prey on other birds. From this knowledge, you reason that eye spots scare away birds that might eat the moth. This is your hypothesis.

Testing the Hypothesis

To test a hypothesis, you first need to make a prediction based on the hypothesis. A prediction is a statement that tells what will happen under certain conditions. It can be expressed in the form: If A occurs, then B will happen. Based on your hypothesis, you might make this prediction: If a moth has eye spots on its wings, then birds will avoid eating it.

Next, you must gather evidence to test your prediction. Evidence is any type of data that may either agree or disagree with a prediction, so it may either support or disprove a hypothesis. Evidence may be gathered by an experiment . Assume that you gather evidence by making more observations of moths with eye spots. Perhaps you observe that birds really do avoid eating moths with eye spots. This evidence agrees with your prediction.

Drawing Conclusions

Evidence that agrees with your prediction supports your hypothesis. Does such evidence prove that your hypothesis is true? No; a hypothesis cannot be proven conclusively to be true. This is because you can never examine all of the possible evidence, and someday evidence might be found that disproves the hypothesis. Nonetheless, the more evidence that supports a hypothesis, the more likely the hypothesis is to be true.

Communicating Results

The last step in a scientific investigation is communicating what you have learned with others. This is a very important step because it allows others to test your hypothesis. If other researchers get the same results as yours, they add support to the hypothesis. However, if they get different results, they may disprove the hypothesis.

5. Theories

Theory vs. theory. Is a scientific theory different from the everyday use of the word theory?

A scientific theory is accepted as a scientific truth , supported by evidence collected by many scientists. 

Scientific Theories

With repeated testing, some hypotheses may eventually become scientific theories. Keep in mind, a hypothesis is a possible answer to a scientific question. A scientific theory is a broad explanation for events that is widely accepted as true. To become a theory, a hypothesis must be tested over and over again, and it must be supported by a great deal of evidence.

People commonly use the word theory to describe a guess about how or why something happens. For example, you might say, “I think a woodchuck dug this hole in the ground, but it’s just a theory.” Using the word theory in this way is different from the way it is used in science. A scientific theory is more like a fact than a guess because it is so well-supported. 

CK-12 Foundation, Biology. http://creativecommons.org/licenses/by-nc-sa/3.0/

6. Why I do Science

Why I do Science

Dan Costa, Ph.D. is a professor of Biology at the University of California, Santa Cruz, and has been studying marine life for well over 40 years. He is a leader in using satellite tags, time and depth recorders and other sophisticated electronic tags to gather information about the amazing depths to which elephant seals dive, their migration routes and how they use oceanographic features to hunt for prey as far as the international dateline and the Alaskan Aleutian Islands. In the following KQED video, Dr. Costa discusses why he is a scientist:http://science.kqed.org/quest/video/why-i-do-science-dan-costa/ .

7. Summary and Vocabulary

Summary

• Science is a way of learning about the natural world that is based on evidence and logic.
• The goal of science is to understand how and why things happen.
• Science advances as new evidence accumulates and allows scientists to replace, refine, or expand on accepted ideas about the natural world.
• At the heart of science is the scientific investigation, which is done by following the scientific method. A scientific investigation is a plan for asking questions and testing possible answers.
• A scientific investigation typically begins with observations. Observations often lead to questions.
• A hypothesis is a possible logical answer to a scientific question, based on scientific knowledge.
• A prediction is a statement that tells what will happen under certain conditions.
• Evidence is any type of data that may either agree or disagree with a prediction, so it may either support or disprove a hypothesis. Conclusions may be formed from evidence.
• The last step in a scientific investigation is the communication of results with others.
• With repeated testing, some hypotheses may eventually become scientific theories. A scientific theory is a broad explanation for events that is widely accepted as true.

Vocabulary

• science: Way of learning about the natural world that is based on evidence and logic.
• evidence: Any type of data that may be used to test a hypothesis.
• experiment: Special type of scientific investigation that is performed under controlled conditions to test a hypothesis.
• prediction: Statement that tells what will happen under certain conditions. 
• hypothesis: Possible answer to a scientific question. It must be possible to prove it wrong.
• theory: A broad explanation for events that is widely accepted as true.

CK-12 Foundation, Physical Science. http://creativecommons.org/licenses/by-nc-sa/3.0/

CK-12 Foundation, Biology. http://creativecommons.org/licenses/by-nc-sa/3.0/