UO1-MSS05_G6_IN 8/17/04 4:12 PM Page 2 HowHow AreAre thethe InuitInuit && AstronautsAstronauts Connected?Connected? 2 Bryan & Cherry Alexander UO1-MSS05_G6_IN 8/17/04 4:12 PM Page 3 or thousands of years, people known as the Inuit have lived in Arctic regions. In Fthe early 1900s, an American naturalist spent time among the Inuit in Canada. The naturalist watched the Inuit preserve fish and meat by freezing them in the cold northern air. Months later, when the people thawed and cooked the food, it was tender and tasted fresh. Eventually, the naturalist returned to the United States, perfected a quick-freezing process, and began marketing frozen foods. Later, inventors found a way to remove most of the water from frozen foods. This process, called freeze-drying, produces a lightweight food that can be stored at room temperature and doesn’t spoil. Freeze-dried foods are carried by all sorts of adventurers—including astronauts. The assessed Indiana objective appears in blue. To find project ideas and resources,visit in6.msscience.com/unit_project. Projects include: • History Contribute to a class time line of inventions from Chinese rockets to liquid fuel,radio communications,space suits,and more. 6.1.7, 6.2.5, 6.2.7 • Technology Research,design,and construct a simple telescope as you study how technology has allowed scientists to explore distant space. 6.1.2, 6.1.7 • Model Investigate the production of space foods,and present an informational commercial to the class. 6.2.5, 6.2.6, 6.2.7, 6.2.9 Investigating the Sun explores the physical characteristics of the sun and energy it produces.Design a labeled diagram of our nearest star. 6.1.7, 6.2.5, 6.2.7, 6.3.17 (l r)NASA, (bkgd)Bryan & Cherry Alexander 634-S1-MSS05_G6_IN 8/17/04 3:45 PM Page 4 Academic Standard—1: Students design investigations. They use computers and other technol- ogy to collect and analyze data; they explain findings and can relate how they conduct investiga- tions to how the scientific enterprise functions as a whole. Students understand that technology has allowed humans to do many things, yet it cannot always provide solutions to our needs. Also covers: Academic Standards 2, 4, 5, 7 (Detailed standards begin on page IN8.) The Nature of Science How is science a par t sections 1 What is science? of your everyday life? 2 Science in Action Scientists studying desert ecosystems in 3 Models in Science California wondered how such a dry environ- ment could produce such beautiful, prolific 4 Evaluating Scientific Explanation Lab What is the right answer? flowers. Scientists began asking questions and Lab Identifying Parts of an Investigation performing investigations. Virtual Lab How is a controlled Science Journal Write down three examples of experiment performed? science in your everyday life. 4 David Keaton/CORBIS 634-S1-MSS05_G6_IN 8/17/04 3:45 PM Page 5 Start-Up Activities Science Make the following Foldable to help identify what you already know, what you Observe How Gravity Accelerates want to know, and what you learned about Objects science. Gravity is a familiar natural force that keeps STEP 1 Fold a vertical sheet you anchored on Earth, but how does it of paper from side to work? Scientists learn about gravity and side. Make the front other concepts by asking questions and edge about 1/2 inch making observations. By observing things shorter than the back in action scientists can study nature. edge. Perform the lab below to see how gravity affects objects. STEP 2 Turn lengthwise and fold into thirds. 1. Collect three identical, unsharpened pencils. 2. Tape two of the pencils together. STEP 3 Unfold and cut only the top layer 3. Hold all the pencils at the same height as along both folds to make three tabs. high as you can. Drop them together and Label each tab. observe what happens as they fall. 4. Think Critically Did the single pencil fall Know? Like to Learned? know? faster or slower than the pair? Predict in your Science Journal what would happen if you taped 30 pencils together and dropped them at the same time as you Identify Questions Before you read the chap- dropped a single pencil. ter, write what you already know about science under the left tab of your Foldable, and write questions about what you’d like to know under Preview this chapter’s content the center tab. After you read the chapter, list and activities at what you learned under the right tab. in6.msscience.com 5 David Keaton/CORBIS 634-S1-MSS05_G6_IN 8/17/04 3:45 PM Page 6 Standards—6.1.1: Explain that some scientific knowledge … is very old and yet is still applicable today… 6.1.2: Give examples of different ways scientists investigate natural phenomena and identify processes all sci- entists use … to make sense of the evidence. Also covers: 6.1.3, 6.1.4, 6.1.5, 6.1.8, 6.1.9, 6.4.13, 6.7.1 (Detailed standards begin on page IN8.) What is science? Learning About the World Nowitz/CORBIS T. on Briel, (r)Richard When you think of a scientist, do you imagine a person in a laboratory surrounded by charts, graphs, glass bottles, and bub- ■ Define science and identify ques- bling test tubes? It might surprise you to learn that anyone who tions that science cannot answer. tries to learn something about the natural world is a scientist. ■ Compare and contrast theories Science is a way of learning more about the natural world. and laws. Scientists want to know why, how, or when something occurred. (l)Jack Star/Photolink/PhotoDisc, (c)Rudi V ■ Identify a system and its This learning process usually begins by keeping your eyes open components. ■ Identify the three main branches and asking questions about what you see. Much of the scientific of science. knowledge we have is very old, but is still being used today. For example, the sequence of moon phases has been known for centuries. Science can be used to learn more about the world you live in. Asking Questions Scientists ask many questions. How do things work? What do things look like? What are they made of? Review Vocabulary Why does something take place? Science can attempt to answer theory: explanation of things or events that is based on knowl- many questions about the natural world, but some questions can- edge gained from many observa- not be answered by science. Look at the situations in Figure 1. tions and experiments Who should you vote for? What does this poem mean? Who is New Vocabulary your best friend? Questions about art, politics, personal prefer- • science • life science ence, or morality can’t be answered by science. Science can’t tell • scientific • Earth science you what is right, wrong, good, or bad. theory • physical • scientific law science • system • technology Figure 1 Questions about politics, literature, and art cannot be answered by science. 634-S1-MSS05_G6_IN 8/17/04 3:45 PM Page 7 Figure 2 As new information Possible outcomes becomes available, explanations Explanation can be modified or discarded and still possible new explanations can be made. Explanation modified Question One New explanation information Explanation discarded New possible explanation Possible Explanations If learning about your world begins with asking questions, can science provide answers to these questions? Science can answer a question only with the informa- tion available at the time. Any answer is uncertain because peo- ple will never know everything about the world around them. With new scientific knowledge, they might realize that some of the old explanations no longer fit the new information. As shown in Figure 2, some observations might force scientists to look at old ideas and think of new explanations. Science can only provide possible explanations. Why can’t science answer questions with certainty? Scientific Theories An attempt to explain a pattern observed repeatedly in the natural world is called a scientific theory. Theories are not simply guesses or someone’s opinions, nor are theories vague ideas. Theories in science must be sup- ported by observations and results from many investigations. They are the best explanations that have been found so far. However, theories can change. As new data become available, scientists evaluate how the new data fit the theory. If enough new data do not support the theory, the theory can be changed to fit the new observations better. Scientific Laws A rule that describes a pattern in nature is a scientific law. For an observation to become a scientific law, it must be observed repeatedly. The law then stands until someone makes observations that do not follow the law. A law helps you predict that an apple dropped from arm’s length will always fall to Earth. The law, however, does not explain why gravity exists or how it works. A law, unlike a theory, does not attempt to explain why something happens. It simply describes a pattern. SECTION 1 What is science? 7 634-S1-MSS05_G6_IN 8/17/04 3:45 PM Page 8 Figure 3 Systems are a collection of structures, cycles, and processes. Infer What systems can you identify in this classroom? Systems in Science Scientists can study many different things in nature. Some might study how the human body works or how planets move around the Sun. Others might study the energy carried in a light- ning bolt. What do all of these things have in common? All of them are systems. A system is a collection of structures, cycles, and processes that relate to and interact with each other.