Lesson 1 Understanding Science Chapter Introduction Lesson 1 Understanding Science Lesson 2 Measurement and Scientific Tools Lesson 3 Case Study Chapter Wrap-Up Chapter Menu

How can science provide answers to your questions about the world around you? Chapter Introduction

Lesson 1 Reading Guide - KC Understanding Science What is scientific inquiry? What are the results of scientific investigations? How can a scientist prevent bias in a scientific investigation? Lesson 1 Reading Guide - KC

Lesson 1 Reading Guide - Vocab Understanding Science science observation inference hypothesis prediction technology scientific theory scientific law critical thinking Lesson 1 Reading Guide - Vocab

What is science? Science is the investigation and exploration of natural events and of the new information that results from those investigations. People use reasoning, creativity, and skepticism in their daily lives to solve problems. Lesson 1-1

Branches of Science Biology, or life science, is the study of all living things. biology from Greek bios, means “life”; and logia, means “study of” Lesson 1-2

Branches of Science (cont.) The study of Earth, including landforms, rocks, soil, and forces that shape Earth’s surface, is Earth science. The study of chemistry and physics is physical science. Lesson 1-2

Scientific Inquiry As scientists study the natural world, they usually use certain skills, or methods. Lesson 1-3

Scientific Inquiry (cont.) A scientist uses a sequence of skills and methods in an investigation. Lesson 1-3

Scientific Inquiry (cont.) Observations often are the beginning of the process of science. An observation is using one or more of your senses to gather information and take note of what occurs. Lesson 1-3

Scientific Inquiry (cont.) A possible explanation about an observation that can be tested by scientific investigations is a hypothesis. A prediction is a statement of what will happen next in a sequence of events. Lesson 1-3

Scientific Inquiry (cont.) When you test a hypothesis, you often are testing your predictions. If your prediction is not confirmed, your hypothesis might need revision. Lesson 1-3

Scientific Inquiry (cont.) What is scientific inquiry? Lesson 1-3

Scientific Inquiry (cont.) The next step in a scientific investigation is to organize and analyze your data. You must determine whether inferences can be made or conclusions drawn from the data. An inference is a logical explanation of an observation that is drawn from prior knowledge or experience. Lesson 1-3

If your hypothesis is not supported, you may need to modify it. If your hypothesis is supported by the data, you can repeat the experiment to confirm the results. If your hypothesis is not supported, you may need to modify it. Lesson 1-3

Scientific Inquiry (cont.) An important step in scientific inquiry is communicating results. Lesson 1-3

Results of Scientific Inquiry In science, you perform scientific inquiry to find answers to questions. The practical use of scientific knowledge, especially for industrial or commercial use is technology. Many times, scientific investigations answer the questions: who, what, when, where, or how. Lesson 1-4

Results of Scientific Inquiry (cont.) What are the results of scientific investigations? Lesson 1-4

Scientific Theory and Scientific Laws A scientific theory is an explanation of observations or events based on knowledge gained from many observations and investigations. A scientific law describes a pattern or an event in nature that is always true. Lesson 1-5

Lesson 1-5

Scientific Theory and Scientific Laws (cont.) Critical thinking is comparing what you already know with the information you are given in order to decide whether you agree with it. To prevent bias in an investigation, sampling, repetition, and blind studies can be helpful. Lesson 1-5

Lesson 1-5

Scientific Theory and Scientific Laws (cont.) How can a scientist prevent bias in a scientific investigation? Lesson 1-5

Scientific Theory and Scientific Laws (cont.) Questions about personal opinions, values, beliefs, and feelings cannot be answered scientifically. Scientists follow safety procedures when they conduct investigations. Ethics are especially important when using living things during investigations. Lesson 1-6

Which is the study of chemistry and physics? A. biology B. Earth science C. life science D. physical science Lesson 1 – LR1

Which term refers to a statement of what will happen next in a sequence of events? A. hypothesis B. inference C. observation D. prediction Lesson 1 – LR2

Which refers to comparing what you already know with the information you are given in order to decide whether you agree with it? A. critical thinking B. inference C. observation D. scientific law Lesson 1 – LR3

Lesson 2 Reading Guide - KC Measurement and Scientific Tools What is the difference between accuracy and precision? Why should you use significant digits? What are some tools used by scientists? Lesson 2 Reading Guide - KC

Lesson 2 Reading Guide - Vocab Measurement and Scientific Tools description explanation International System of Units (SI) accuracy precision significant digits Lesson 2 Reading Guide - Vocab

Description and Explanation A description is a spoken or written summary of observations. An explanation is an interpretation of observations. When you explain something, you try to interpret your observations, which can lead to a hypothesis. Lesson 2-1

The International System of Units The International System of Units (SI) is an internationally accepted system for measurement. All SI units are derived from seven base units. Lesson 2-2

The International System of Units (cont.) A prefix can be added to a base unit’s name to indicate either a fraction or a multiple of that base unit. Prefixes are based on powers of ten, such as 0.01 and 100. Lesson 2-2

Accuracy is a description of how close a measurement is to an accepted or true value. Precision is a description of how similar or close measurements are to each other. Lesson 2-2

The data taken by student A are more accurate because each value is close to the accepted value. The data taken by student C are more precise because the data are similar. Lesson 2-2

The International System of Units (cont.) How do accuracy and precision differ? Lesson 2-2

Measurement and Accuracy All measurements have some uncertainty. The tools used to make measurements limit the accuracy of the measurements. Lesson 2-3

Significant Digits Significant digits are the number of digits in a measurement that are known with a certain degree of reliability. The significant digits in a measurement include all digits you know for certain plus one estimated digit. Lesson 2-4

Lesson 2-4

Significant Digits (cont.) Using significant digits lets others know how certain your measurements are. Lesson 2-4

Significant Digits (cont.) Why should you use significant digits? Lesson 2-4

Scientific Tools Science journals are for recording descriptions, explanations, plans, and steps used in scientific inquiry. Corbis Lesson 2-5

Scientific Tools (cont.) A triple-beam balance or a digital balance is used by scientists to measure mass. The McGraw-Hill Companies, Inc./Stephen Frisch, photographer Lesson 2-5

Scientific Tools (cont.) A thermometer measures the temperatures of substances. The McGraw-Hill Companies Inc./Ken Cavanagh Photographer Lesson 2-5

Scientific Tools (cont.) Flasks, beakers, petri dishes, test tubes, and specimen jars are used as containers. Lesson 2-5

Scientific Tools (cont.) Graduated cylinders are used to measure the volume of a liquid. The unit of measure for liquid volume is the liter (L) or milliliter (mL). Lesson 2-5

Scientific Tools (cont.) Microscopes, such as dissecting microscopes and compound light microscopes, enable you to observe small objects that you cannot observe with just your eyes. Photodisc/Getty Images Lesson 2-5

Scientific Tools (cont.) Scientists use computers to compile, retrieve, and analyze data for reports. Lesson 2-5

Tools Used by Life Scientists A magnifying lens is a hand-held lens that magnifies, or enlarges, an image of an object. To observe items using a compound light microscope, you must place it on a thin, rectangular piece of glass called a slide. Lesson 2-6

Tools Used by Life Scientists (cont.) Scientists use dissecting tools, such as scalpels and scissors, to examine tissues, organs, or prepared organisms. A pipette is a small glass or plastic tube used to draw up and transfer liquids. Ingram Publishing/SuperStock Photodisc Collection/Getty Images Lesson 2-6

Tools Used by Life Scientists (cont.) What are some tools used by life scientists? Lesson 2-6

Which term refers to a description of how close a measurement is to an accepted or true value? A. accuracy B. explanation C. precision D. significant digit Lesson 2 – LR1

Which can be added to a base unit’s name to indicate either a fraction or a multiple of that base unit? A. SI unit B. significant digit C. prefix D. description Lesson 2 – LR2

Which of these is used by scientists to measure mass? A. microscope B. petri dish C. thermometer D. triple-beam balance Lesson 2 – LR3

Lesson 3 Reading Guide - KC Case Study How do independent and dependent variables differ? How is scientific inquiry used in a real-life scientific investigation? Lesson 3 Reading Guide - KC

Lesson 3 Reading Guide - Vocab Case Study variable dependent variable independent variable constants Lesson 3 Reading Guide - Vocab

Biodiesel from Microalgae During the past few decades, scientists have explored using protists to produce biodiesel fuel. Protists are a group of microscopic organisms that usually live in water or moist environments. Lesson 3-1

Designing a Controlled Experiment Scientists use scientific inquiry to investigate the use of protists to make biodiesel. They design controlled experiments to test their hypotheses. A controlled experiment is a scientific investigation that tests how one variable affects another. Lesson 3-2

Designing a Controlled Experiment (cont.) A variable is any factor in an experiment that can have more than one value. In controlled experiments, there are two types of variables: dependent variables and independent variables. Lesson 3-2

Designing a Controlled Experiment (cont.) The dependent variable is the factor measured or observed during an experiment. The independent variable is the factor that you want to test. It is changed by the investigator to observe how it affects a dependent variable. Lesson 3-2

Designing a Controlled Experiment (cont.) How do independent and dependent variables differ? Lesson 3-2

Designing a Controlled Experiment (cont.) Constants are the factors in an experiment that remain the same. Lesson 3-2

Designing a Controlled Experiment (cont.) A controlled experiment has two groups—an experimental group and a control group. The experimental group is used to study how a change in the independent variable changes the dependent variable. The control group contains the same factors as the experimental group, but the independent variable is not changed. Lesson 3-2

Biodiesel Rudolph Diesel invented the diesel engine using peanut oil to demonstrate how it worked. Oil-rich food crops, such as soybeans, can be used as a source of biodiesel. NPS Photo by Jim Peaco Lesson 3-3

Aquatic Species Program In the late 1970s, the U.S. Department of Energy began funding its Aquatic Species Program (ASP) to investigate ways to remove air pollutants. The program’s focus shifted to using microalgae to produce oils that could be processed into biodiesel. Lesson 3-4

Which Microalgae? Microalgae are microscopic organisms that live in marine or freshwater environments, use photosynthesis, and make sugar. Scientists collected and identified promising microalgae species, focusing on microalgae they predicted were more resistant to changes in temperature and salt content in water. Lesson 3-5

Oil Production in Microalgae Some studies suggested that starving microalgae of nutrients, such as nitrogen, could increase the amount of oil they produced. Starving microalgae caused them to be smaller, resulting in no overall increase in oil production. Lesson 3-6

Outdoor Testing v. Bioreactors Three methods of growing microalgae are examples of different hypotheses being tested in controlled experiments. Open ponds are less expensive than bioreactors for growing microalgae. Microalgae grown in plastic bags are very expensive to harvest. Microalgae grow under controlled conditions in glass bioreactors. Lesson 3-6

Why So Many Hypotheses? According to Dr. Richard Sayre, a biofuel researcher, all the ASP research was based on forming hypotheses. Lesson 3-6

Increasing Oil Yield Scientists from a biofuel company in Washington State wondered if they could increase microalgae oil production by distributing light to all microalgae. Lesson 3-6

Bringing Light to Microalgae Data from experiments showed scientists how microalgae in well-lit environments grow compared to how microalgae grow in dimmer environments. Scientists plan to take light to microalgae instead of moving microalgae to light. Light rods and paddlewheels were both used to bring light to microalgae. Lesson 3-6

Bringing Light to Microalgae (cont.) Describe three ways in which scientific inquiry was used in this case study. Lesson 3-6

Why Grow Microalgae? In addition to growing microalgae for biodiesel production, there are other benefits of growing microalgae. Not only do microalgae produce a valuable fuel, they also remove pollutants from and add oxygen to the atmosphere. Lesson 3-6

Lesson 3-6

Are microalgae the future? The costs of growing microalgae and extracting their oils are too high to compete with petroleum-based diesel. The combined efforts of government-funded programs and commercial biofuel companies might one day make microalgae-based biodiesel and affordable reality in the United States. Lesson 3-6

C. controlled experiment D. experimental group Which term describes a scientific investigation that tests how one variable affects another? A. constants B. control group C. controlled experiment D. experimental group Lesson 3 – LR1

Which is a factor in an experiment that remains the same? A. constant B. dependent variable C. independent variable D. variable Lesson 3 – LR2

C. controlled experiment D. variable Which contains the same factors as the experimental group, but does not have the independent variable changed? A. constant B. control group C. controlled experiment D. variable Lesson 3 – LR3

Standardized Test Practice Key Concept Summary Chapter Review Standardized Test Practice Chapter Review Menu

You can answer questions about your world by using scientific inquiry to creatively construct investigations and collect and evaluate appropriate data through observations and inferences. The BIG Idea

Lesson 1: Understanding Science Scientific inquiry, also known as scientific methods, is a collection of skills that scientists use in different combinations to perform scientific investigations. Scientific investigations often result in new technology, new materials, newly discovered objects or events, or answers to questions. A scientist can help prevent bias in a scientific investigation by taking random samples, doing blind studies, repeating an experiment several times, and keeping accurate and honest records. Key Concepts 1

Lesson 2: Measurement and Scientific Tools Precision is a description of how similar or close measurements are to each other. Accuracy is a description of how close a measurement is to an accepted value. Significant digits communicate the precision of the tool used to make measurements. Life scientists use many tools, such as science journals, microscopes, computers, magnifying lenses, slides, and dissecting tools. Key Concepts 2

Lesson 3: Case Study: Biodiesel from Microalgae The independent variable is a factor in an experiment that is manipulated or changed by the investigator to observe how it affects a dependent variable. The dependent variable is the factor measured or observed during an experiment. Scientific inquiry is used to gain information and find solutions to real life problems and questions. Key Concepts 3

Which term refers to the investigation and exploration of natural events and of the new information that results from those investigations? A. inference B. reasoning C. science D. skepticism Chapter Review – MC1

Which term describes a logical explanation of an observation that is drawn from prior knowledge or experience? A. hypothesis B. inference C. prediction D. scientific law Chapter Review – MC2

Which term describes how similar or close measurements are to each other? A. accuracy B. base unit C. precision D. significant digit Chapter Review – MC3

A. compound light microscope B. graduated cylinder C. thermometer Which enables scientists to observe small objects that cannot be observed with just eyes? A. compound light microscope B. graduated cylinder C. thermometer D. triple-beam balance Chapter Review – MC4

Which term refers to the factor that you test in an experiment? A. constant B. control group C. dependent variable D. independent variable Chapter Review – MC5

Which describes a pattern or an event in nature that is always true? A. critical thinking B. hypothesis C. scientific law D. scientific theory Chapter Review – STP1

Which term describes a possible explanation about an observation that can be tested by scientific investigations? A. hypothesis B. inference C. observation D. prediction Chapter Review – STP2

Which term refers to the digits in a measurement that are known with a certain degree of reliability? A. base B. constant C. SI D. significant Chapter Review – STP3

Which is used by scientists to measure the volume of a liquid? A. petri dish B. microscope C. graduated cylinder D. computer Chapter Review – STP4

D. independent variable Which term refers to the factor measured or observed during an experiment? A. constant B. dependent variable C. experimental group D. independent variable Chapter Review – STP5