What Is Science? Read the lesson title aloud to students. Tell students that scientists have an ongoing goal to explain things in our world. Scientists discover new information about our world all the time, but cannot answer all questions. Discussion: Challenge students to think of questions that can be answered in science and questions that cannot be answered in science. Discuss a few examples of each type of question. Science can be applied to any question where the answer can be observed, researched, investigated or measured, or in other words where evidence can be found. Science cannot answer questions if evidence is not available. (Example: What is the purpose of life?)

Learning Objectives State the goals of science. Describe the steps used in scientific methodology. Click to reveal each of the learning objectives. Have students work with a partner to discuss the question: Why study science? Have volunteers share their answers with the class. Possible response: We should study science to learn more about the world around us. Then ask students: How would you describe biology? What do you already know about it? Accept all reasonable responses. Students may answer that biology is the study of all life. They may describe previous science courses they have taken that involved biology.

The Nature of Science Science Uses evidence to construct testable explanations and predictions of natural phenomena Generates knowledge Tell students that science is the use of evidence to construct testable explanations and predictions of natural phenomena, as well as the knowledge generated through this process. Ask students the following questions to promote their understanding of what science is about. Ask: How do you “know” about something? Sample answer: You learn about something, or you see it for yourself. Ask: Where does knowledge come from? Sample answer: from people who study particular topics Ask: What does it mean to say that science is a process? Sample answer: The word process indicates that science is something people do, rather than just a group of facts. Ask: Do you think the phrase “a way of knowing” accurately describes science as a method of learning? Why or why not? Sample answer: Yes, the phrase identifies science as a method or tool used to learn about the natural world. Discuss that one goal of science is to provide natural and testable explanations for events in the natural world. Science also aims to use explanations supported by data to understand patterns in nature, and to make useful predictions about natural events. Discuss that science rarely “proves” anything because as we continue to gather more evidence, our understanding of the world continues to improve.

Scientific Methodology: Observation Scientific methodology is a general style of investigation, not a rigid step-by-step process. Many students have been taught in the past that the “scientific method” is a set of five or six simple steps performed by all scientists, always in the same order. Tell students: Scientists use these steps, but not always in the same order or way. Scientific methodology describes a general style of investigation that applies across branches of science. Ask: What is meant by a general style? Answer: Scientists carry out investigations in a similar way, but not an identical way. Explain that scientific investigations begin with observation, the act of noticing and describing events or processes in a careful, orderly way. Ask students to describe the difference between the grasses at these two locations. Answer: The grasses in location B are taller than those in location A. This observation led to a question: Why do marsh grasses grow to different heights in different places?

Scientific Methodology: Asking Questions Why do marsh grasses grow to different heights in different places? Tell students: All scientific investigations involve asking questions. To answer questions, scientists try to focus on one specific factor. Ask: Why study only one factor at a time when asking a question? Answer: Studying more than one factor makes it impossible to tell if observed changes are from one factor or the other. Accurate explanations cannot be reached. Ask: If a scientist were to study how both the amount of light and the amount of water affected plant growth at the same time, what would the observations and data show? Answer: It would be impossible to tell if changes in the plants were due to light or water differences. Ask students to hypothesize what may be causing these differences. Write all reasonable answers on the board. Sample answers: temperature, sunlight, water, nutrients Click to reveal the factor studied in this experiment: nitrogen

Scientific Methodology: Hypothesis what scientists already know Inference: a logical interpretation based on Hypothesis: a tentative scientific explanation that can be tested further Ask a volunteer to come to the board and fill in the rest of the definition of “inference.” Click to reveal the answer. Ask a volunteer to come to the board and fill in the rest of the definition of “hypothesis.” Explain that scientists would make an inference based on prior knowledge and use that to generate a hypothesis. To set up the next slide, discuss with the class how they might test this hypothesis.

Scientific Methodology: Experiment Testing hypotheses often involves designing experiments that measure factors that can change, or variables. Ask: Can you identify any differences between these two plots? Answer: There are no differences. Ask: What are some conditions in these plots that can change or be changed? Sample answers: soil type, amount of light received, amount of water received Click to reveal the control group and experimental group. Explain the basic experimental design shown in the image. Tell students that in an experiment there are two groups, and both have all of the same factors/variables except one. A scientist will change one variable in the experimental group. Ask: What variable changed in the example? Answer: Nitrogen was added. Tell students this variable changed by the scientist is called the independent or manipulated variable. The group with the independent variable is the experimental group and the group without it is the control group. Scientists expect the independent variable to cause a change in some other factor. Ask students: In this case, what change occurred due to the independent variable? Answer: the height of the grass, or the rate of growth of the grass Tell students the factor that changed in response to the independent variable is called the dependent or responding variable. Remind students all other variables should be the same between the two plots. Explain that a controlled experiment is an experiment where only one variable differs between the groups being tested. Ask: Can you list some examples of controlled variables for this experiment? Answers: plant density, soil type, input of freshwater, height above tide level

Scientific Methodology: Collecting Data Quantitative Qualitative data are numbers. data are descriptive. Tell students there are two kinds of data: data that can be measured in number form and data based on observations. Data with numbers represent distinct quantities and are therefore called quantitative data. Data that describe things with words are called qualitative data. Ask a volunteer to fill in the sentences on the board with the words “qualitative” or “quantitative.” Click to reveal the answers. Draw students’ attention to the slide. Ask: What type of data did scientists collect in our example? Answer: They measured the height of the grass in the control and experimental groups. Ask: Is this an example of quantitative or qualitative data? Answer: quantitative Ask: Can you think of an example of qualitative data that could have been collected? Sample answer: grass color Have students make a two-column table. Have them label the left side of the table Qualitative Data and the right side Quantitative Data. Have them list additional examples of qualitative and quantitative data that might be collected in this experiment. Sample answers: Quantitative data could include the number of plants per plot, or the length, width, and weight of each blade of grass. Qualitative data might include the presence of an unexpected object in a plot or the presence of a plant disease on some leaves.

Scientific Methodology: Analyzing Data Data analysis in science often relies on the use of statistics. Ask students: What is this graph is showing? Answer: The graph shows that the experimental group (which got the independent variable of extra nitrogen) grew taller than the control group (which did not get nitrogen). Tell students that reading graphs and patterns in data is called analyzing data. Based on analysis, scientists can make a conclusion for that particular experiment. Ask students: What is the conclusion of this experiment? Answer: The nitrogen caused the grass to grow higher. Tell students that once a conclusion has been made based on the data analysis, a scientist will often go back to the original hypothesis and revise it or do another similar experiment. Ask students: How could the experiment in our example be refined or expanded? Sample answers: The experiment could be repeated with more or less nitrogen or a different kind of nutrient. Explain that hypothesis-based experiments are not always possible. For example, sometimes scientists have no initial information on which to make a hypothesis, such as when studying animal behavior in the wild.

Scientific Methodology: Review Tell students: An example of an observation is that students who get more sleep seem to do better in school. Ask students: Now that we have an observation, what is the next step in the process, according to scientific methodology? Click to reveal the answer: hypothesis Ask a volunteer to develop a testable hypothesis for this observation. Come to a consensus as a class and write the hypothesis on the board. Sample answer: Students who get 8 hours of sleep get higher grades in their classes. Ask students: What is the next step in the process? Click to reveal the answer: experiment Lead the class in designing a simple experiment. Outline the experiment on the board. Sample answer: On the day of a test, ask students to state how much sleep they got the night before. Ask: Is a controlled experiment possible in this case? Answer: No, because students would have had different foods for breakfast, different levels of stress, and would have studied for different amounts of time. Ask: What are the independent and dependent variables in the study? Answer: independent: amount of sleep; dependent: grade on test Ask: What is the next step in the process? Click to reveal the answer: observation and data analysis Ask students to draw a mock graph of results. Have a volunteer draw his or her graph on the board. Click to reveal answer: interpretation Explain that the interpretation of results can lead to a number of different outcomes. Click to reveal the final portion of the chart. Explain that the data may result in the hypothesis being supported or not. If the hypothesis is not supported, the various steps can be revisited. Ask each student or pair of students to come up with a sample experimental question to test. Have the student(s) write out an example for each part of the process based on the sample question they came up with.