Holt McDougal Earth Science Chapter 1 PDF

1 SECTION What Is Earth Science? Key ey y Ideas deass Key ey y Terms...

1 SECTION What Is Earth Science? Key ey y Ideas deass Key ey y Terms e s Why y Itt Matters atte s ❯ Describe two cultures that contributed to mod- Earth science Earth scientists help us ern scientific study. geology understand our place in ❯ Name the four main branches of Earth science. Earth’s history and in the oceanography universe. They can also ❯ Discuss how Earth scientists help us understand meteorology help us gain access to the world around us. Earth’s resources and use astronomy these resources wisely. F or thousands of years, people have looked at the world around them and wondered what forces shaped it. Throughout history, many cultures have been terrified and fascinated by seeing volca- noes erupt, feeling the ground shake during an earthquake, or watching the sky darken during an eclipse. Some cultures developed myths or stories to explain these events. Modern science searches for natural causes and uses care- ful observations to explain these same events and to understand Earth and its changing landscape. The Scientific Study of Earth Scientific study of Earth began with careful observations. Scientists in China began keeping records of earthquakes as early as 780 bce. The ancient Greeks compiled a catalog of rocks and min- erals around 200 bce. Other ancient peoples, including the Maya, Earth science the scientific tracked the movements of the sun, the moon, and the planets at study of Earth and the universe observatories like the one shown in Figure 1. The Maya used these around it observations to create accurate calendars. For many centuries, scientific discoveries were limited to observations of phenomena that could be seen with the unaided eye. Then, in the 16th and 17th centuries, the inventions of the microscope and the telescope made seeing previously hidden worlds possible. Eventually, the body of knowledge about Earth became known as Earth science. Earth science is the study of Earth and of the universe around it. Earth science, like other sciences, assumes that natural events, or phenomena, can be explained through careful observation and experimentation. Figure 1 El Caracol, an observatory built by the ancient Maya of Central America, is one of the oldest known observatories in the Americas. Mayan calendars include the celestial movements that the Maya tracked by using observatories. Section 1 What Is Earth Science? 5  Branches of Earth Science The ability to make observations improves when technology, such as new processes or equipment, is developed. Technology has Spider Map allowed scientists to explore the ocean depths, Earth’s unseen Create a spider map that interior, and the vastness of space. Earth scientists have used summarizes the branches of Earth science. Use the green technology and hard work to build an immense body of knowledge heads in this section as the legs about Earth. of your spider map, Most Earth scientists specialize in one of four major areas of and add one or study: the solid Earth, the oceans, the atmosphere, and the uni- two branches to verse beyond Earth. Examples of Earth scientists working in these each leg. areas are shown in Figure 2. Geology The study of the origin, history, processes, and structure of the geology the scientific study of solid Earth is called geology. Geology includes many specialized the origin, history, and structure areas of study. Some geologists explore Earth’s crust for deposits of Earth and the processes that shape Earth of coal, oil, gas, and other resources. Other geologists study the forces within Earth to predict earthquakes and volcanic eruptions. oceanography the scientific study of the ocean, including Some geologists study fossils to learn more about Earth’s past. the properties and movements Often, new knowledge forms new areas of study. of ocean water, the characteris- tics of the ocean floor, and the Oceanography organisms that live in the ocean Oceans cover nearly three-fourths of Earth’s surface. The study of Earth’s oceans is called oceanography. Some oceanographers Academic Vocabulary work on research ships that are equipped with special instruments technology (tek NAHL uh jee) tools, for studying the sea. Other oceanographers study waves, tides, including electronic devices and ocean currents. Some oceanographers explore the ocean floor to obtain clues to Earth’s history or to locate mineral deposits. Figure 2 Fields of Study in Earth Science This meteorologist is studying ice samples to learn about past Thi This astronomer t iis lilinking ki a climate. Studying past climate telescope with a specialized patterns gives scientists Geologists who study volcanoes are instrument called a spectrograph. information about possible called volcanologists. This volcanologist is Information gathered will help future changes in climate. measuring the properties of moving lava. her catalog the composition of more than 100 galaxies. 6 Chapter 1 Introduction to Earth Science Why It Matters More than a Pretty Picture Scientists use a variety of instruments and methods to study Earth. For example, common methods for studying climate change include analyzing ice cores and tree rings. Now, one innovative scientist has turned instead to art. Scientists know that volcanic ash in the atmosphere blocks sunlight, which causes temperatures to drop. Could painting shed light on past temperatures? J.M.W. Turner made the top painting three years before a volcanic eruption in the Philippines in 1831. 1 He made the bottom painting in 1833. The redder sunset in the CRITICAL THINKING bottom painting was How could studying paintings by caused by volcanic ash. different artists affect scientists’ conclusions? Meteorology The study of Earth’s atmosphere is called meteorology meteorology. Using meteorology the scientific satellites, radar, and other technologies, meteorologists study the study of Earth’s atmosphere, especially in relation to weather atmospheric conditions that produce weather. Many meteorolo- and climate gists work as weather observers and measure factors such as wind astronomy the scientific study speed, temperature, and rainfall. This weather information is then of the universe used to prepare detailed weather maps. Other meteorologists use weather maps, satellite images, and computer models to make weather forecasts. Some meteorologists study climate, the patterns of weather that occur over long periods of time. Astronomy The study of the universe beyond Earth is called astronomy. www.scilinks.org Astronomy is one of the oldest branches of Earth science. In fact, Topic: Branches of Earth Science the ancient Babylonians charted the positions of planets and stars Code: HQX0191 nearly 4,000 years ago. Modern astronomers use Earth-based and space-based telescopes as well as other instruments to study the sun, the moon, the planets, and the universe. Technologies such as rovers and space probes have also provided astronomers with new information about the universe. What information is used for weather maps? (See Appendix G for answers to Reading Checks.) Section 1 What Is Earth Science? 7  Environmental Science and Earth Science Some Earth scientists study the ways in which humans interact with their environment in a relatively new field of science called environmental science. Many fields of study, such as Earth science, biology, and the social sciences, contribute to environmental science. The goal of environ- mental science is to understand and solve problems that result from how we use natural resources and how our actions affect the environment. The Importance of Earth Science Natural forces not only shape Earth but also affect life on Earth. For example, a volcanic eruption may bury a town under ash. And an earthquake may produce huge ocean waves that destroy shorelines. By understanding how nat- ural forces shape our environment, Earth scientists, such as those in Figure 3, can better predict potential disasters and help save lives and property. The work of Earth scientists also helps us understand our place in the universe. Astronomers studying distant Figure 3 These meteorologists are risking their lives to gather galaxies have come up with new ideas about the origins of information about tornadoes. If our universe. Geologists studying rock layers have found clues to scientists can better predict Earth’s past environments and to the evolution of life on this when tornadoes will occur, many planet. lives may be saved each year. Earth provides the resources that make life as we know it pos- sible. Earth also provides the materials to enrich the quality of peo- ple’s lives. The fuel that powers a jet, the metal used in surgical instruments, and the paper and ink in this book all come from Earth’s resources. The study of Earth science can help people gain access to Earth’s resources, but Earth scientists also strive to help people use those resources wisely. Section 1 Review Key Ideas Critical Thinking 1. Discuss how one culture contributed to modern 6. Analyzing Ideas How have Earth scientists science. improved our understanding of the environment? 2. Name the four major branches of Earth science. 7. Analyzing Concepts Give two examples of how 3. Describe two specialized fields of geology. exploring space and exploring the ocean depths are similar. 4. Describe the work of oceanographers and meteorologists. Concept Mapping 5. Explain how the work of astronomers has been 8. Use the following terms to create a concept map: affected by technology. Earth science, geology, meteorology, climate, environmental science, astronomy, and oceanography. 8 Chapter 1 Introduction to Earth Science  2 SECTION Science as a Process Key ey y Ideas deass Key ey y Terms e s Why y Itt Matters atte s ❯ Explain how science is different from other forms observation Science helps us under- of human endeavor. hypothesis stand Earth, nature, and ❯ Identify the steps that make up scientific the universe. Science also independent variable helps us apply our knowl- methods. dependent variable edge to develop tech- ❯ Analyze how scientific thought changes as new nologies which, in turn, information is collected. peer review help us solve problems ❯ Explain how science affects society. theory and improve the condi- tion of human society. A rt, architecture, philosophy, and science are all forms of human endeavor. Although artists, architects, and philosophers may use science in their work, science does not have the same goals as other human endeavors do. The goal of science is to explain natural phenomena. Scientists ask questions about natural events and then work to answer those questions through experiments and examination. Scientific under- standing moves forward through the work of many scientists, who build on the research of the generations of scientists before them. Behavior of Natural Systems Scientists start with the assumption that nature is understand- able, and they expect that similar forces in a similar situation will cause similar results. But the forces involved in natural events are Figure 1 Scientists use ice complex. For example, changes in temperature and humidity can cores to study past composi- cause rain in one city, but the same changes in temperature and tions of Earth’s atmosphere. humidity may cause fog in another city. These different results This information can help scientists learn about past might be due to differences in the two cities or due to complex climate changes. issues, such as differences in climate. Scientists also expect that nature is predictable, which means that the future behavior of natural forces can be antici- pated. So, if scientists understand the forces and materials involved in a process, they can predict how that process will evolve. The scientists in Figure 1, for example, are studying ice cores in Antarctica. Ice cores can provide clues to Earth’s past climate changes. Because natural systems are complex, however, a high level of understanding and predictability can be diffi- cult to achieve. To increase their understand- ing, scientists follow the same basic processes of studying and describing natural events. 9  Scientific Methods Over time, the scientific community has developed organized and logical approaches to scientific research. These approaches are known as scientific methods. Scientific methods are not a set of sequential steps that scientists always follow. Rather, these meth- ods are guidelines to scientific problem solving. Figure 2 shows a basic flowchart of scientific methods. Ask a Question observation the process of Scientific methods often begin with observations. Observation obtaining information by using is the process of using the senses of sight, touch, taste, hearing, the senses; the information obtained by using the senses and smell to gather information about the world. When you see hypothesis a testable idea or thunderclouds form in the summer sky, you are making an obser- explanation that leads to vation. And when you feel cool, smooth, polished marble or hear scientific investigation the roar of river rapids, you are making observations. Observations can often lead to questions. What causes torna- does to form? Why is oil discovered only in certain locations? What causes a river to change its course? What causes some plants to grow faster than others? Simple questions such as these have fueled years of scientific research and have been investigated through sci- entific methods. Form a Hypothesis Once a question has been asked and basic information has been gathered, a scientist may propose a tentative answer, which is also known as a hypothesis (hie PAHTH uh sis). A hypothesis (plural, hypotheses) is a possible explanation or solution to a problem. www.scilinks.org Topic: Scientific Methods Hypotheses can be developed through close and careful observa- Code: HQX1359 tion. Most hypotheses are based on known facts about similar events. One example of a hypothesis is that plants that are given a large amount of sunlight will grow faster than plants given a smaller amount of sunlight. This hypothesis could be made from observing how and where other plants grow. Name two ways scientific methods depend on careful observations. Figure 2 Scientific Method Flowchart Making Asking Forming a Testing a Drawing Communicating C observations questions hypothesis hypothesis h conclusions c results 10 Chapter 1 Introduction to Earth Science  Figure 3 Astronaut Shannon Lucid observes wheat plants as a part of a controlled experiment in orbit around Earth. independent variable in an experiment, the factor that is deliberately manipulated dependent variable in an experiment, the factor that changes as a result of manipulation of one or more Test the Hypothesis other factors (the independent After a hypothesis is proposed, it is often tested by performing variables) experiments. An experiment is a procedure that is carried out according to certain guidelines. Factors that can be changed in an experiment are variables. Independent variables are factors that are changed by the person performing the experiment. Dependent variables are variables that change as a result of a change in inde- Quick Lab 5 min pendent variables. In most experiments, only one independent variable is tested. Making For example, to test how sunlight affects plants, a scientist would Observations grow identical plants. The plants would receive the same amount of water and fertilizer but different amounts of sunlight. Thus, Procedure sunlight would be the independent variable. How the plants 1 Get an ordinary candle of respond to the different amounts of sunlight would be the depen- any shape and color. dent variable. Most experiments include a control group. A control 2 Record all the observations group is a group that serves as a standard of comparison with you can make about the another group to which the control group is identical except for candle. one factor. In this experiment, the plants that receive a natural 3 Light the candle with a amount of sunlight would be the control group. An experiment match, and watch it burn for 1 min. that contains a control is called a controlled experiment. Most sci- 4 Record as many observa- entific experiments are controlled experiments. The “zero gravity” tions about the burning experiment shown in Figure 3 is a controlled experiment. candle as you can. When you are finished, extinguish Draw Conclusions the flame. Record any observations. After many experiments and observations, a scientist may reach conclusions about his or her hypothesis. If the hypothesis fits Analysis the known facts, it may be accepted as true. If the experimental 1. Share your results with your results differ from what was expected, the hypothesis may be class. How many things that changed or discarded. Expected and unexpected results lead to your classmates observed new questions and further study. The results of scientific inquiry did you not observe? may also lead to new knowledge and new methods of inquiry that Explain this phenomenon. further scientific aims. Section 2 Science as a Process 11 Good accuracy and good precision Poor accuracy but good precision Good overall accuracy but poor precision Figure 4 Accuracy and Precision Scientific Measurements and Analysis During an experiment, scientists must gather information. An important method of gathering information is measurement. Keyword: HQXIESF4 Measurement is the comparison of some aspect of an object or event with a standard unit. Scientists around the world can com- pare and analyze each other’s measurements because scientists use a common system of measurement called the International System of Units, or SI. This system includes standard measurements for length, mass, temperature, and volume. All SI units are based on intervals of 10. The Reference Tables section of the Appendix con- tains a chart of SI units. Accuracy and Precision Accuracy and precision are important in scientific measure- ments. Accuracy refers to how close a measurement is to the true value of the thing being measured. Precision is the exactness of the measurement. For example, a distance that is measured in millime- ters is more precise than a distance that is measured in centimeters. Measurements can be precise and yet inaccurate. The relationship between accuracy and precision is shown in Figure 4. Quick Lab Sample Size and Accuracy 15 min Procedure Analysis 1 Shuffle a deck of 52 playing cards eight times. 1. A deck of cards has 50% red cards. How close is 2 Lay out 10 cards. Record the number of red your average to the percentage of red cards in the cards. deck? 3 Reshuffle, and repeat step 2 four more times. 2. Pool the results of your classmates. How close is the new average to the percentage of red cards in 4 Which trials showed the highest number and the deck? lowest number of red cards? Calculate the total range of red cards by finding the difference 3. How does between the highest number and lowest changing the number. sample size affect accuracy? 5 Determine the mean number of red cards per trial by adding the number of red cards in the five trials and then dividing by 5. 12 Chapter 1 Introduction to Earth Science Error Error is an expression of the amount of imprecision or varia- tion in a set of measurements. Error is commonly expressed as percentage error or as a confidence interval. Percentage error is the percentage of deviation of an experimental value from an accepted value. A confidence interval describes the range of values for a set percentage of measurements. For example, imagine that Percentage Percen ercen ntage Error the average length of all of the ears of corn in a field is 23 cm, and Percentage error is calculated by using the following 90% of the ears are within 3 cm of the average length. A scientist equation: may report that the average length of all of the ears of corn in a field is 23 ± 3 cm with 90% confidence. (accepted value — percent experimental value) error ! " 100 accepted value Observations and Models In Earth science, using controlled experiments to test a hypoth- If the accepted value for the esis is often impossible. When experiments are impossible, scientists weight of a gallon of water is make additional observations to gather evidence. The hypothesis is 3.78 kg and the measured then tested by examining how well the hypothesis fits or explains all value is 3.72 kg, what is the percentage error for the of the known evidence. measurement? Show your Scientists also use models to simulate conditions in the natural work. world. A model is a description, representation, or imitation of an object, system, process, or concept. Scientists use several types of models, two of which are shown in Figure 5. Physical models are three-dimensional models that can be touched. Maps and charts are examples of graphical models. Conceptual models are verbal or graphical models that repre- sent how a system works or is organized. Mathematical models are mathematical equations that represent the way a system or process works. Computer models are a kind of mathematical model that use the high speed and efficiency of a computer to make calculations and display results. After a good computer Figure 5 Two models of model has been created, scientists can perform experiments by Mount Everest are shown manipulating variables much as they would when performing a below. The computer model on physical experiment. the right is used to track erosion along the Tibetan Plateau. The Name three types of models. model on the left is a physical model. Mt. Everest Section 2 Science as a Process 13 Figure 6 Meteorologists at a conference in California are watching the “Science On a Sphere™” exhibit. They are wearing 3-D glasses to better see the complex and changing three-dimensional display of global temperatures. Acceptance of Scientific Ideas When scientists reach a conclusion, they introduce their find- ings to the scientific community. New scientific ideas undergo Spider Map review and testing by other scientists before the ideas are Create a spider map that accepted. outlines the process that new scientific ideas go through before they are accepted by the Publication of Results and Conclusions scientific community. Label the Scientists commonly present the results of their work in scien- center of your spider map tific journals or at professional meetings, such as the one shown in “Acceptance of a new scientific Figure 6. Results published in journals are usually written in a idea,” and create a leg for each standard scientific format. Many journals are now being published part of the process. online to allow scientists quicker access to the results of other sci- Add details about each part of the entists and to reduce the costs of printing journals. process to its cor- responding leg. Peer Review Scientists in any one research group tend to view scientific ideas similarly. Therefore, they may be biased in their experimen- tal design or data analysis. To reduce bias, scientists submit their peer review the process in ideas to other scientists for peer review. Peer review is the process which experts in a given field in which several experts on a given topic review another expert’s examine the results and conclusions of a scientist’s study work on that topic before the work gets published. These experts before that study is accepted for determine if the results and conclusions of the study merit publica- publication tion. Peer reviewers commonly suggest improvements to the study, or they may determine that the results or conclusions are flawed and recommend that the study not be published. Scientists follow an ethical code that states that only valid experimental results should be published. The peer review process serves as a filter that allows only well-supported ideas to be published. Name two places scientists present the results of their work. 14 Chapter 1 Introduction to Earth Science  Formulating a Theory After results are published, they usually lead to more experi- ments, which are designed to test and expand the original idea. This process may continue for years until the original idea is dis- proved, is modified, or becomes generally accepted. Sometimes, Academic Vocabulary elements of different ideas are combined to form concepts that are concept (KAHN sept) an idea or a more complete. thought When an idea has undergone much testing and reaches gen- eral acceptance, that idea may help form a theory. A theory is an theory a system of ideas that explanation that is consistent with all existing tests and observa- explains many related tions. Theories are often based on scientific laws. A scientific law is observations and is supported by a large body of evidence a general statement that describes how the natural world behaves acquired through scientific under certain conditions and for which no exceptions have been investigation found. Like theories, laws are discovered through scientific research. Theories and scientific laws can be changed if conflicting information is discovered in the future. The Importance of Interdisciplinary Science Scientists from many disciplines commonly contribute the information necessary to support an idea. The free exchange of ideas between fields of science allows scientists to identify expla- nations that fit a wide range of scientific evidence. When an explanation is supported by evidence from a variety of fields, the explanation is more likely to be accurate. New disciplines of sci- ence sometimes emerge as a result of new connections that are found between more than one branch of science. An example of the development of a widely accepted hypothesis that is based on interdisciplinary evidence is shown in Figure 7. Figure 7 The hypothesis that the dinosaurs were killed by an asteroid impact was developed Impact Hypothesis over many years and through of Extinction of the the work of many scientists from Dinosaurs different disciplines. Paleontology Geology Astronomy Climatology photo photo photo photo No dinosaur fossils exist A large impact crater A layer of iridium occurs Climate models predict in rock layers younger than about 65 million years in rocks about 65 million that a large impact would 65 million years old. old exists in the ocean near years old all around Earth. change Earth's climate and the Yucatan Peninsula. Iridium is rare on Earth, affect life on Earth. but is common in asteroids. Section 2 Science as a Process 15  Science and Society Scientific knowledge helps us understand our world. The work of people, including scientists, is influenced by their cul- tural and personal beliefs. Science is a part of society, and advances in science can have important and long-lasting effects on both science and society. Examples of these far-reaching advances include the theory of plate tectonics, quantum mechanics, and the theory of evolution. Figure 8 The Alaskan pipeline has carried more than 15 billion Science is also used to develop new technology, including barrels of oil since it was built in new tools, machines, materials, and processes. Sometimes, technolo- 1977. The pipeline has also gies are designed to address a specific human need. In other cases, sparked controversy about the technology is an indirect result of science that was directed at another potential dangers to nearby goal. For example, technology that was designed for space explora- Alaskan wildlife. tion has been used to improve computers, cars, medical equipment, and airplanes. However, new technology may also create new problems. Scientists involved in research that leads to new technologies may or may not consider the possible negative effects of their work. Before making decisions about the technology they adopt, people should consider alternatives, risks, and costs and benefits to humans, to other life, and to Earth. Even after decisions are made, society often continues to debate them. For example, the Alaskan www.scilinks.org pipeline, part of which is shown in Figure 8, transports oil. But the Topic: Careers in Earth transport of oil in the United States is part of an ongoing debate Science Code: HQX0222 about how we use oil resources and how these uses affect our natu- ral world. Section 2 Review Key Ideas Critical Thinking 1. Describe one reason that a scientist might 9. Analyzing Ideas An observation can be conduct research. precise but inaccurate. Do you think it is pos- 2. Identify the steps that make up scientific sible for an observation to be accurate but not methods. precise? Explain. 10. Making Comparisons When an artist paints a 3. Compare a hypothesis with a theory. picture of a natural scene, what aspects of his or 4. Describe how scientists test hypotheses. her work are similar to the methods of a scien- 5. Describe the difference between a dependent tist? What aspects are different? variable and an independent variable. 11. Demonstrating Reasoned Judgment A new 6. Describe the conditions under which scientific technology is known to be harmful to a small laws and theories can be changed. group of people. How does this knowledge affect whether you would use this new technol- 7. Summarize how scientific methods contribute ogy? Explain. to the development of modern science. 8. Explain how technology can affect scientific Concept Mapping research. 12. Use the following terms to create a concept map: independent variable, observation, experi- ment, dependent variable, hypothesis, scientific methods, and conclusion. 16 Chapter 1 Introduction to Earth Science Why It Matters How Do Robots Go to Extremes? Scientific observation is not always easy. Earth scientists often need to go to extreme places to make observations and gather data. But some places are too extreme, even for the most daring scientists. How can scientists gather R Robovolc explores data in places that are too cold, too vvolcanoes and collects hot, too deep, or too far away? ssamples to analyze. The answer, more and more often, is Its six rugged wheels It robots. Robots can be designed to kkeep it stable on jagged withstand extreme conditions, such as vvolcanic terrain. Its intense cold. They also can be outfitted gripper is engineered to g with special tools and abilities for their pick up rock samples. p missions. For example, one robot, which was designed for research in Antarctica, hovers like a helicopter and flies at speeds up to 100 km/h. It uses a DEPTHX, an underwaterater camera and infrared sensor to observe rover, can be loweredd the ice below. Another robot is hundreds of meters designed to glide across snowy slopes into deep, uncharted and icy crevasses. sinkholes such as El Zacatón cenote in central Mexico. Mars Science Laboratory (MSL) is the next-generation Mars rover. Its lab equipment will la help scientists study h Mars’s geology, and M possible biology, in p greater detail than g ever before. e Micro Micro-scale nanobots are so small that their components can be single molecules! As shown in sing ONLINE RESEARCH this artwork, this technology thi may one day produce devices m How is the Mars Science that can enter the human th Laboratory rover similar to the bloodstream and target specific blo current Mars rovers, Spirit and cells or viruses. cel Opportunity? How is it different? 17  Inquiry Lab 90 min Scientific Methods What You’ll Do Not all scientists think alike, and scientists don’t always agree about ❯ Observe natural various concepts. However, all scientists use scientific methods, part of phenomena. which are the skills of observing, inferring, and predicting. In this lab, you will apply scientific methods as you examine a place where puddles ❯ Propose hypotheses to often form after rainstorms. You can study the puddle area even when explain natural phenomena. the ground is dry, but it would be best to observe the area again when ❯ Evaluate hypotheses. it is wet. Because water is one of the most effective agents of change in our environment, you should be able to make many observations. What You’ll Need hand lens meterstick Make Observations 1 Examine the area of the puddle an and the surrounding area carefully. Make a numbered list of what can be seen, heard, smelled, or felt. Sample observations are as follows: “The ground where the puddle forms is lower than the surrounding area, and there are cracks in the soil.” Remember to avoid making any suggestions of causes. Form a Hypothesis 2 Review your observations observations, and wr write possible hypotheses for those observations. A sample hypothesis might be “Cracks in the soil (Observation 2) may have been caused by a lack of rain (Observation 5).” 3 Review your observations and possible hypotheses, and place them into similar groups, if possible. Can one hypothesis or set of hypotheses explain several observations? Is each hypothesis reasonable when compared with the others? Does any hypothesis contradict any of the other observations? Step 1 18  Chapter 1 Review 1. Word Parts Write the word astronomy and its 14. The Earth scientist most likely to study definition. Then use a dictionary to look up the volcanoes is a(n) meanings of astro- and -nomy. Do a. geologist. this for two more words that have b. meteorologist. the suffix -nomy. c. oceanographer. d. astronomer. USING KEY TERMS 15. One possible first step in scientific problem solving is to Use each of the following terms in a separate a. form a hypothesis. sentence. b. ask a question. 2. observation c. test a hypothesis. 3. peer review d. state a conclusion. 4. theory 16. A possible explanation for a scientific problem is called a(n) For each pair of terms, explain how the meanings a. experiment. c. observation. of the terms differ. b. theory. d. hypothesis. 5. hypothesis and theory 17. A statement that consistently and correctly 6. geology and astronomy explains a natural phenomenon is 7. oceanography and meteorology a. a hypothesis. c. an observation. 8. dependent variable and independent variable b. a theory. d. a control. 9. Earth science and geology 18. When scientists pose questions about how nature operates and attempt to answer those questions through testing and observation, UNDERSTANDING KEY IDEAS they are conducting 10. The study of solid Earth is called a. research. c. examinations. a. geology. c. oceanography. b. predictions. d. peer reviews. b. meteorology. d. astronomy. 11. The Earth scientist most likely to study storms SHORT ANSWER is a(n) a. geologist. 19. How does accuracy differ from precision in a b. meteorologist. scientific measurement? c. oceanographer. 20. Why do scientists use control groups in d. astronomer. experiments? 12. The study of the origin of the solar system and 21. A meteorite lands in your backyard. What two the universe in general is branches of Earth science would help you a. geology. explain that natural event? b. ecology. 22. Write a short paragraph about the relationship c. meteorology. between science and technology. d. astronomy. 23. Give two reasons why interdisciplinary science 13. How long ago were the first scientific is important to society. observations about Earth made? 24. Explain how peer review affects scientific a. a few years ago knowledge. b. a few decades ago 25. How did some ancient cultures explain natural c. hundreds of years ago phenomena? d. several thousand years ago 22 Chapter 1 Introduction to Earth Science