Nature of Science

Ck12 Science

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Printed: September 16, 2015

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CHAPTER 1 Nature of Science• Define science.• Explain the goal of science.• Describe how science advances knowledge.• Design a scientific experiment.

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 thatit comes from a Latin word that means “having knowledge.” However, this isn’t an adequate definition either.

What Is Science?

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

The Goal of Science

Scientists may focus on very different aspects of the natural world. For example, some scientists focus on the worldof tiny objects, such as atoms and molecules. Other scientists devote their attention to huge objects, such as the sunand other stars. But all scientists have at least one thing in common. They want to understand how and why thingshappen. 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 1.1? Fireworksshow how the goal of science leads to discovery. Fireworks were invented at least 2000 years ago in China, butexplaining how and why they work didn’t happen until much later. It wasn’t until scientists had learned aboutelements and chemical reactions that they could explain what caused fireworks to create brilliant bursts of light anddeep rumbling booms.

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FIGURE 1.1Fireworks were invented long before scientists could actually explain howand why they explode.

How Science Advances

Sometimes learning about science is frustrating because scientific knowledge is always changing. But that’s alsowhat 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 Newtonintroduced the idea that gravity is universal. People had long known that things fall to the ground because they areattracted by Earth. But Newton proposed that everything in the universe exerts a force of attraction on everythingelse. 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 alwaysfall down toward the ground or roll downhill. It also explains the motion of many other objects. For example, itexplains why planets orbit the sun. The idea of universal gravity even helped scientists discover the planets Neptuneand Pluto. The caption and diagram in the Figure 1.2 explain how.

Baby steps in science occur as small bits of evidence gradually accumulate. The accumulating evidence lets scientistsrefine 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 acceptedat first, and scientists may be mocked for their ideas. The idea that Earth’s continents drift on the planet’s surfaceis a good example. This idea was first proposed by a scientist named Alfred Wegener in the early 1900s. Wegeneralso proposed that all of the present continents had once formed one supercontinent, which he named Pangaea (seeFigure 1.3). Other scientists not only rejected Wegener’s ideas, but ridiculed Wegener for even suggesting them. Itwasn’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 beenfound on continents that are now separated by oceans. It is also now known that Earth’s crust consists of rigidplates that slide over molten rock below them. This explains how continents can drift. Even the shapes of today’scontinents show how they once fit together, like pieces of a giant jigsaw puzzle.

Summary

• Science is a way of learning about the natural world that is based on evidence and logic.

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FIGURE 1.2In the early 1800s, astronomers noticeda wobble in Uranus’ orbit around thesun. They predicted that the wobblewas caused by the pull of gravity of an-other, not-yet-discovered planet. Scien-tists searched the skies for the “missing”planet. When they discovered Neptune in1846, they thought they had found theirmissing planet. After the astronomerstook into account the effects of Neptune’sgravity, they saw that Uranus still hadan unexplained wobble. They predictedthat there must be another planet be-yond Neptune. That planet, now calledPluto, was finally discovered in 1930. Ofspecial note, as of 2006, the Interna-tional Astronomical Union (IAU) demotedPluto from its planet status as it doesnot meet one of the criteria for plan-etary standards. For more informationsee: http://www.nature.com/news/2006/060821/full/news060821-11.html

FIGURE 1.3This map shows the supercontinent Pan-gaea, which was first proposed by Al-fred Wegener. Pangaea included all ofthe separate continents we know today.Scientists now know that the individualcontinents drifted apart to their presentlocations over millions of years.

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• 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.

Explore More

Try to answer the students’ questions about the nature of science in the animation below. Then click on the answersto see if you are correct.

http://evolution.berkeley.edu/evosite/nature/IIIQuiz.shtml#

Review

1. Define science.2. What is the goal of science?3. Use examples to show how science may advance.

References

1. Bob Jagendorf. Fireworks . CC BY 2.02. Flickr: Image Editor. The Solar System . CC BY 2.03. Laura Guerin. The supercontinent Pangaea . CC BY-NC 3.0

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Scientific Problem Solving

Ck12 Science

Say Thanks to the AuthorsClick http://www.ck12.org/saythanks

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To access a customizable version of this book, as well as otherinteractive content, visit www.ck12.org

CK-12 Foundation is a non-profit organization with a mission toreduce the cost of textbook materials for the K-12 market both inthe U.S. and worldwide. Using an open-source, collaborative, andweb-based compilation model, CK-12 pioneers and promotes thecreation and distribution of high-quality, adaptive online textbooksthat can be mixed, modified and printed (i.e., the FlexBook®textbooks).

Copyright © 2015 CK-12 Foundation, www.ck12.org

The names “CK-12” and “CK12” and associated logos and theterms “FlexBook®” and “FlexBook Platform®” (collectively“CK-12 Marks”) are trademarks and service marks of CK-12Foundation and are protected by federal, state, and internationallaws.

Any form of reproduction of this book in any format or medium,in whole or in sections must include the referral attribution linkhttp://www.ck12.org/saythanks (placed in a visible location) inaddition to the following terms.

Except as otherwise noted, all CK-12 Content (including CK-12Curriculum Material) is made available to Users in accordancewith the Creative Commons Attribution-Non-Commercial 3.0Unported (CC BY-NC 3.0) License (http://creativecommons.org/licenses/by-nc/3.0/), as amended and updated by Creative Com-mons from time to time (the “CC License”), which is incorporatedherein by this reference.

Complete terms can be found at http://www.ck12.org/about/terms-of-use.

Printed: September 16, 2015

AUTHORCk12 Science

www.ck12.org Chapter 1. Scientific Problem Solving

CHAPTER 1 Scientific Problem Solving

• Describe the approach of the ancient Greek philosophers to understanding the world around them.• Define inductive and deductive reasoning.• Describe the scientific method.

How can we use problem solving in our everyday routines?

One day you wake up and realize your clock radio did not turn on to get you out of bed. You are puzzled, so youdecide to find out what happened. You list three possible explanations:

1. There was a power failure and your radio cannot turn on..2. Your little sister turned it off as a joke.3. You did not set the alarm last night.

Upon investigation you find that the clock is on, so there is no power failure. Your little sister was spending thenight with a friend and could not have turned the alarm off. You notice that the alarm is not set – your forgetfulnessmade you late. You have used the scientific method to find an answer to a question.

Scientific Problem Solving

Humans have always wondered about the world around them. One of the questions of interest was (and still is) whatis this world made of? Chemistry has been defined in various ways as the study of matter. What that matter consistsof has been a source of debate over the centuries. One of the key arenas for this debate in the Western world wasGreek philosophy.

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The basic approach of these philosophers to questions about the world was discussion and debate. There was nogathering of information to speak of, just talking. As a result, several ideas about matter were put forth, but neverresolved. The first philosopher to carry out the gathering of data was Aristotle (384-322 B.C.). He recorded manyobservations on the weather, on plant and animal life and behavior, on physical motions, and a number of othertopics. Aristotle could probably be considered the first “real” scientist since he made systematic observations ofnature and tried to understand what he was seeing.

FIGURE 1.1Aristotle.

Inductive and Deductive Reasoning

Two approaches to logical thinking developed over the centuries. These two methods are inductive reasoning anddeductive reasoning. Inductive reasoning involves getting a collection of specific examples and drawing a generalconclusion from them. Deductive reasoning takes a general principle and then draws a specific conclusion from thegeneral concept. Both are used in the development of scientific ideas.

Inductive reasoning first involves the collection of data. If I add sodium metal to water, I will observe a very violentreaction. Every time I repeat the process, I see the same thing happening. I draw a general conclusion from theseobservations: the addition of sodium to water results in a violent reaction.

In deductive reasoning, I make a specific prediction based on a general principle. One general principle is that acidsturn blue litmus paper red. If I have a bottle of liquid labeled “acid,” I expect the litmus paper to turn red when Iimmerse it in the liquid.

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The Idea of the Experiment

Inductive reasoning is at the heart of what we call the “ scientific method.” In European culture, this approach wasdeveloped mainly by Francis Bacon (1561-1626), a British scholar. He advocated the use of inductive reasoning inevery area of life, not just science. The scientific method as developed by Bacon and others involved several steps:

1. ask a question – identify the problem to be considered2. make observations – gather data that pertains to the question3. propose an explanation ( a hypothesis) for the observations4. make new observations to test the hypothesis further

FIGURE 1.2Sir Francis Bacon.

Note that this should not be considered a “cookbook” for scientific research. Scientists do not sit down with theirdaily “to do” list and write down these steps. The steps may not necessarily be followed in order. But this doesprovide a general idea of how scientific research is usually done.

When a hypothesis is confirmed repeatedly, it eventually becomes a theory – a general principle that is offered toexplain natural phenomena. Note a key word – explanation. The theory offers a description of why somethinghappens. A law, on the other hand, is a statement that is always true, but does not explain why. The law of gravitysays a rock will fall when dropped, but does not explain why (gravitational theory is very complex and incompleteat present). The kinetic-molecular theory of gases, on the other hand, tells what happens when a gas is heated ina closed container (the pressure increases), but also explains why (the motions of the gas molecules are increaseddue to the change in temperature). Theories do not get “promoted” to laws because laws do not answer the “why”question.

Summary

• The early Greek philosophers spend their time talking about nature, but did little or no actual exploration orinvestigation.

• inductive reasoning – developing a general conclusion from a collection of observations.• deductive reasoning – making a specific statement based on a general principle.• scientific method – a process of observation, developing a hypothesis, and testing that hypothesis.

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Explore More

Use the link below to answer the following questions:

• Deductive Reasoning vs. Inductive Reasoning at http://www.livescience.com/21569-deduction-vs-induction.html .

1. Describe deductive reasoning.2. Develop your own example of deductive reasoning.3. What is a syllogism?4. Describe inductive reasoning.5. What is adductive reasoning?

Review

1. What was the basic shortcoming of the Greek philosophers approach to studying the material world?2. How did Aristotle improve the approach?3. Define “inductive reasoning” and give an example.4. Define “deductive reasoning” and give an example.5. What is the difference between a hypothesis and a theory?6. What is the difference between a theory and a law?

• deductive reasoning: Takes a general principle and then draws a specific conclusion from the general concept.Used in the development of scientific ideas.

• inductive reasoning: Involves getting a collection of specific examples and drawing a general conclusionfrom them. Used in the development of scientific ideas.

• scientific method: This approach was developed by Francis Bacon (1561-1626), a British scholar. Inductivereasoning is at the heart. of this method. The steps include: ask a question (identify the problem to be consid-ered), make observations (gather data that pertains to the question), propose an explanation (a hypothesis) forthe observations, make new observations to test the hypothesis further.

References

1. Derek Jensen (Wikimedia: Tysto). http://commons.wikimedia.org/wiki/File:Digital-clock-alarm.jpg .2. Raphael. http://commons.wikimedia.org/wiki/File:Aristotle_by_Raphael.jpg .3. Paul van Somer. http://commons.wikimedia.org/wiki/File:Sir_Francis_Bacon.jpg .

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