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Understanding ScienceRead to Learn

What is science?Did you ever hear a bird sing and then look in nearby trees

to find the singing bird? Have you ever noticed how theMoon changes from a thin crescent to a full moon eachmonth? When you do these things, you are doing science.Science is the investigation and exploration of natural events and ofthe new information that results from those investigations.

For thousands of years, men and women of all countriesand cultures have studied the natural world and recordedtheir observations. They have shared their knowledge andfindings and have created a vast amount of scientificinformation. Scientific knowledge has been the result of agreat deal of debate and confirmation within the sciencecommunity.

People use science in their everyday lives and careers.For example, firefighters wear clothing that has beendeveloped and tested to withstand extreme temperatures andnot catch fire. Parents use science when they set up anaquarium for their children's pet fish. Athletes use sciencewhen they use high-performance gear or wear high-performance clothing.

Without thinking about it, you use science or the resultsof science in almost everything you do. Most likely, yourclothing, food, hair products, electronic devices, athleticequipment, and almost everything else you use are all resultsof science.

Branches of ScienceThere are many different parts of the natural world.

Because there is so much to study, a scientist often focuses hisor her work in one branch of science or on one topic withinthat branch of science. There are three main branches ofscience—Earth science, life science, and physical science. @

Key Concepts t°_^'• What is scientific inquiry?• How do scientific laws and

scientific theories differ?• What is the difference

between a fact and anopinion?

Identify the Main Ideas Asyou read, write one sentenceto summarize the main ideain each paragraph. Write themain ideas on a sheet ofpaper or in your notebook tostudy later.

Reading Check

1. Name the three mainbranches of science.

Reading Essentials Methods of Science NOS 1

[^^ Key Concept Check2. Define What is scientificinquiry?

fw) Visual Check3.5tate What are fourpossible ways to test ahypothesis?

Observeand

Question

State a ProblemGather Information• Infer

Earth Science The study of Earth, including rocks, soils, oceans,the atmosphere, and surface features, is Earth science. Earthscientists might ask questions such as, How do differentshorelines react to tsunamis? Why do planets orbit the Sun?What is the rate of climate change?

Life Science The study of living things is life science, orbiology. Biologists ask questions such as, Why do some treeslose their leaves in winter? How do birds know whichdirection they are going? How do mammals control theirbody temperature?

Physical Science The study of matter and energy is physicalscience. It includes both physics and chemistry. Physicistsand chemists ask questions such as, What chemical reactionsmust take place to launch a spaceship into space? Is itpossible to travel faster than the speed of light? What makesup matter?

Scientific InquiryWhen scientists conduct scientific investigations, they

use scientific inquiry. Scientific inquiry is a process that usesa set of skills to answer questions or to test ideas aboutthe natural world. There are many kinds of scientificinvestigations and many ways to conduct them. The seriesof steps used in each investigation often varies. Theflowchart in the figure below and on the next page shows anexample of the skills used in scientific inquiry. ("<^3>

Steps in Scientific Inquiry

^ Repeat severaltimes to confirm

Hypothesizeand

Predict

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Test Hypothesis• Design an Experiment•Make a Model•Gather and Evaluate

Evidence or Research. Collect Data/Record

Observations

L Modify/ReviseHypothesis

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Ask QuestionsOne way to begin a scientific inquiry is to observe the

natural world and ask questions. Observation /5 the act of usingone or more of your senses to gather information and taking note ofwhat occurs. Suppose you observe that the banks of a riverhave eroded more this year than last year. You want to knowwhy. You note that there was an increase in rainfall this year.After these observations, you make an inference based onthese observations. An inference is a logical explanation of anobservation that is drawn from prior knowledge or experience. You inferthat the increase in rainfall caused the increase in erosion.

You decide to investigate further. You develop a hypothesisand a method to test it. @

Hypothesize and Predict/I hypothesis /s a possible explanation for an observation that can

be tested by scientific investigations. A hypothesis states anobservation and provides an explanation. You might makethe following hypothesis: More of the riverbank eroded thisyear because the amount, the speed, and the force of theriver water increased.

Scientists often use a hypothesis to make predictions.A prediction ;5 a statement of what will happen next in a sequence ofevents. Scientists make predictions based on what informationthey think they will find when testing their hypothesis.A prediction for the hypothesis above might be: If rainfallincreases, then the amount, the speed, and the force of riverwater will increase. If the amount, the speed, and the forceof river water increase, then there will be more erosion. @

Steps in Scientific Inquiry

Hypothesissupported

4

Analyze Results• Graph ResultsClassify InformationMake CalculationsOther Processes

DrawConclusions• Infer•Summarize

fHypothesis

not supported

Reading Check

4.5elect Which of thefollowing is a way to begin ascientific inquiry? (Circle thecorrect answer.)

a. observe the naturalworld

b. ask questionsC. both a and b above

Reading Check

5. Identify What doscientists often use to makea prediction?

Communicate Results

• Write Science Journal Articles• Speak at Science Conferences• Exchange Information on Internet• Other Ways of ExchangingInformation

Reading Essentials Methods of Science NOS3

Reading Check

6. Apply When should youmodify your hypothesis?

Make a six-tab book toorganize your notes abouta scientific inquiry.

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Reading Check7. Describe What is thenextstep if a scientist'shypothesis is supported?

Test HypothesisWhen you test a hypothesis, you often test whether your

predictions are true. If your prediction is confirmed, then itsupports your hypothesis. If your prediction is not confirmed,you might need to modify your hypothesis and retest it.

There are several ways to test a hypothesis whenperforming a scientific investigation. You might design anexperiment, make a model, gather and evaluate evidence orresearch, or collect data and record your observations. Forexample, you might make a model of a riverbank in whichyou change the speed and the amount of water and recordobservations and results. ^

Analyze ResultsAfter testing your hypothesis, you analyze your results

using different methods. Often, it is hard to see trends orrelationships in data while collecting it. Data should besorted, graphed, or classified in some way. After analyzingthe data, additional inferences can be made.

Draw ConclusionsOnce you find the relationships among data and make

several inferences, you can draw conclusions. A conclusion isa summary of the information gained from testing ahypothesis. Scientists study the available information anddraw conclusions based on that information.

Communicate ResultsAn important part of the scientific inquiry process is

communicating results. Ways to communicate results-include writing science journal articles, speaking at scienceconferences, and exchanging information on the Internet.Scientists might share their information in other ways, too.

Scientists communicate results of investigations to informother scientists about their research and the conclusions

of their research. Scientists might apply each other'sconclusions to their own work to help support theirhypotheses.

Further Scientific InquiryScientific inquiry is not completed once one scientific

investigation is completed. If predictions are correct and thehypothesis is supported, scientists will retest the predictionsseveral times to make sure the conclusions are the same

each time. If the hypothesis is not supported, any newinformation gained can be used to revise the hypothesis.Hypotheses can be revised and tested many times. @

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Results of ScienceThe results and conclusions from an investigation can

lead to many outcomes, such as the answers to a question,more information on a specific topic, or support for ahypothesis. Other outcomes are described in the followingparagraphs.

Technology A technical solution can be the answer to ascientific question, such as, "How can the hearing impairedhear better?" After investigation, experimentation, andresearch, the conclusion might be the development of a newtechnology. Technology /'s the practical use of scientific knowledge,especially for industrial or commercial use. Technology, such as acochlear implant, can help some deaf people hear. ^New Materials Space travel has unique challenges. Astronautsmust carry oxygen to breathe. They also must be protectedagainst temperature and pressure extremes, as well as small,high-speed flying objects. A spacesuit consists of 14 layersof material. The outer layer is made of a blend of threematerials. One material is waterproof. Another protectsagainst high-speed flying objects. The third material is heatand fire-resistant.

Possible Explanations Scientists often perform investigationsto find explanations as to why or how something happens,such as, "How do stars form?" For example, to help answerthis question, NASA'S Spitzer Space Telescope took photosshowing a cloud of gas and dust with newly formed stars. @Scientific Theory and Scientific Law

Another outcome of science is the development ofscientific theories and laws. Recall that a hypothesis is apossible explanation about an observation that can be testedby scientific investigations.

What happens when a hypothesis or a group of hypotheseshas been tested many times and has been supported by therepeated scientific investigations? The hypothesis canbecome a scientific theory. @

Reading Check8. Define What istechnology?

Reading Check

9. Express What are someresults of science?

Reading Check

10. Explain How can ahypothesis become ascientific theory?

Reading Essentials Methods of Science NOS5

Q^> Key Concept Check11. Differentiate Howdo scientific laws andtheories differ?

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Q Visual Check12. Name two possibleresults from new informationopposing a theory.

Scientific TheoryOften, the word theory is used in casual conversations to

mean an untested idea or an opinion. However, scientistsuse the word theory differently. A scientific theory /'s anexplanation of observations or events that is based on knowledgegained from many observations and investigations.

Scientists question scientific theories and test them forvalidity. A scientific theory generally is accepted as true untilit is disproved. An example of a scientific theory is thetheory of plate tectonics. The theory explains how Earth'scrust moves and why earthquakes and volcanoes occur.

Scientific LawA scientific law is different from a social law, which is an

agreement among people concerning a behavior. A scientificlaw is a rule that describes a pattern in nature. Unlike a scientifictheory that explains why an event occurs, a scientificlaw only states that an event will occur under certaincircumstances. For example, Newton's law of gravitationalforce implies that if you drop an object, it will fall towardEarth. Newton's law does not explain why the object movestoward Earth when dropped, only that it will. ["*^r7

New InformationScientific information constantly changes as new

information is discovered or as previous hypotheses areretested. New information can lead to changes in scientifictheories as explained below. When new facts are revealed, acurrent scientific theory might be revised to include the new_facts, or it might be disproved and rejected.

Supports Theory

New Information

Opposes Theory

If new information supports a current scientifictheory, then the theory is not changed.Theinformation might be published in a scientificjournal to show further support of the theory.The new information might also lead toadvancements in technology or spark newquestions that lead to new scientificinvestigations.

If new information opposes, or does notsupport a current scientific theory, the theorymight be modified or rejected altogether. Often,new information will lead scientists to look atthe original observations in a new way. This canlead to new investigations with newhypotheses. These investigations can lead tonew theories.

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Evaluating Scientific EvidenceDid you ever read an advertisement that made

extraordinary claims, such as the one shown below? If so,you probably practice critical thinking. Critical thinking iscomparing what you already know with the information you are givenin order to decide whether you agree with it. To determine whetherinformation is true and scientific or pseudoscience(information incorrectly represented as scientific), youshould be skeptical and identify facts and opinions. Thishelps you evaluate the strengths and weaknesses ofinformation and make informed decisions. Critical thinkingis important in all decision making—from everyday decisionsto community, national, and international decisions. @f—>

SkepticismTo be skeptical is to doubtthe truthfulness or accuracyof something. Because ofskepticism, science can beself-correcting. If someonepublishes results or if aninvestigation gives resultsthat don't seem accurate, askeptical scientist usually willchallenge the informationand test the results foraccuracy.

Identifying FactsThe prices of the pillows andthe savings are facts. A fact isa measurement, observation,or statement that can bestrictly defined. Manyscientific facts can beevaluated for their validitythrough investigations.

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Q<~^' Key Concept Check13. Contrast Refer to thefigure below. How do a factand an opinion differ?

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Identifying OpinionsAn opinion is a personalview, feeling, or claim abouta topic. Opinions are neithertrue nor false.

Mixing Facts and OpinionsSometimes people mix factsand opinions. You must readcarefully to determine whichinformation is fact and whichis opinion.

Reading Essentials Methods of Science NOS 7

ACADEMIC VOCABULARYpoteiitial(adjective) possible, likely,or probable

14.1nfer Why should youwear protective clothing andequipment when performingscientific investigations?

Science cannot answer all questions.Scientists recognize that some questions cannot be

studied using scientific inquiry. Questions that deal withopinions, beliefs, values, and feelings cannot be answeredthrough scientific investigation. For example, questionsthat cannot be answered through scientific investigationmight include

• Are comedies the best kinds of movies?

• Is it ever okay to lie?

• Which food tastes best?

The answers to all of these questions are based on opinions,not facts.

Safety in ScienceIt is very important for anyone performing scientific

investigations to use safe practices. You should always followyour teacher's instructions. If you have questions aboutpotential hazards, use of equipment, or the meaning of safetysymbols, ask your teacher. Always wear protective clothingand equipment while performing scientific investigations.If you are using live animals in your investigations, provideappropriate care and ethical treatment to them. Your teachercan help you find more information about the treatment oflive animals.

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