The document explains the nature of science, focusing primarily on methods for solving scientific problems, including descriptive and experimental research. Descriptive research involves observation and a structured methodology to avoid bias and ensure data accuracy, while experimental research tests hypotheses through controlled variables. Key steps such as stating objectives, designing research, analyzing data, and communicating results are emphasized for both research types.

1. Chapter: The Nature of Science Section 3: Science and Technology Section 1: What is science? Section 2: Doing Science 2

2. Solving Problems—Identify the Problem Although the investigation of each problem is different, scientists use some steps in all investigations. Scientists first make sure that everyone working to solve the problem has a clear understanding of the problem. Sometimes, scientists find that the problem is easy to identify or that several problems need to be solved. Doing Science 2

3. How can the problem be solved? Two of the methods used to answer questions are descriptive research and experimental research design. Descriptive research answers scientific questions through observation. Experimental research design is used to answer scientific questions by testing a hypothesis through the use of a series of carefully controlled steps. Doing Science 2

4. How can the problem be solved? Scientific methods are ways, or steps to follow, to try to solve problems. Doing Science 2

5. Descriptive Research Some scientific problems can be solved, or questions answered, by using descriptive research. Doing Science 2 Descriptive research is based mostly on observations. Descriptive research can be used in investigations when experiments would be impossible to perform. Descriptive research usually involves the following steps.

6. 1. State the Research Objective (on the right) This is the first step in solving a problem using descriptive research. Doing Science 2 A research objective is what you want to find out , or what question you would like to answer.

7. 2. Describe the Research Design How will you carry out your investigation? How will the data be recorded and analyzed? Doing Science 2 An important part of any research design is safety . These are a few of the things scientists think about when they design an investigation using descriptive research.

8. Describe the Research Design While investigating a cholera outbreak in the 1800s, Dr. John Snow, included the map in his research design. Doing Science 2

9. Describe the Research Design Doing Science 2 He used these data to predict that the water from the Broad Street pump was the source of the contamination. The map showed where people with cholera had lived, and where they obtained their water.

10. 3. Eliminate Bias Sometimes, scientists might expect certain results. This is known as bias . Doing Science 2 Good investigations avoid bias. One way to avoid bias is to use careful numerical measurements for all data. Another type of bias can occur in surveys or groups that are chosen for investigations. To get an accurate result, you need to use a random sample.

11. 4. Equipment, Materials, and Models When a scientific problem is solved by descriptive research, the equipment and materials used to carry out the investigation and analyze the data are important. Doing Science 2

12. 5. Selecting Your Materials Scientists try to use the most up-to-date materials available to them. Doing Science 2 If possible, you should use scientific equipment such as balances, spring sales, microscopes, and metric measurements when performing investigations and gathering data.

13. Selecting Your Materials Doing Science 2 Calculators and computers can be helpful in evaluating or displaying data.

14. Selecting Your Materials However, you don’t have to have the latest or most expensive materials and tools to conduct good scientific investigations. Doing Science 2 Your investigations can be completed successfully and the data displayed with materials found in your home or classroom. An organized presentation of data is as effective as a computer graphic or an extravagant display.

15. 6. Using Models One part of carrying out the investigation plan might include making or using scientific models. Doing Science 2 In math/science, models are used for things that happen too slowly, too quickly, or are too big or too small to observe directly . Models also are useful in situations in which direct observation would be too dangerous or expensive .

16. Using Models Dr. John Snow’s map of the cholera epidemic was a model that allowed him to predict possible sources of the epidemic. Doing Science 2 Many kinds of models are made on computers. Graphs, tables, and spreadsheets are models that display information.

17. Scientific Methods Doing Science 2 This common language allows them to understand each other’s research and compare results. Scientists around the world use a system of measurements called the International System of Units, or SI , to make observations.

18. Scientific Methods Because SI uses certain metric units that are based on units of ten, multiplication and division are easy to do. Doing Science 2 Prefixes are used with units to change their names to larger or smaller units. K H D U D C M

19. Data — Designing Your Data Tables A well-planned investigation includes ways to record results and observations accurately. Doing Science 2 Data tables are one way to do this.

20. Data—Designing Your Data Tables Doing Science 2 Most tables have a title that tells you at a glance what the table is about. The table is divided into columns and rows. These are usually trials or characteristics to be compared.

21. Data—Designing Your Data Tables Doing Science 2 The first row contains the titles of the columns. The first column identifies what each row represents.

22. Analyze Your Data Your data must be organized to analyze them. Doing Science 2 Charts and graphs are excellent ways to organize data. You can draw the charts and graphs or use a computer to make them.

23. Draw Conclusions After you have organized your data, you are ready to draw a conclusion. Doing Science 2 Sometimes, your data are not what you expected, but remember, scientists understand that it is important to know when something doesn’t work . A successful investigation is not always the one that comes out the way you originally predicted.

24. Communicating Your Results Every investigation begins because a problem needs to be solved. Doing Science 2 Analyzing data and drawing conclusions are the end of the investigation. Usually, scientists communicate their results to other scientists, government agencies, private industries, or the public. Scientists usually publish their most important findings.

25. Communicating Your Results You can communicate your data and conclusions to other members of your science class. Doing Science 2 Organized data and careful analysis will enable you to answer most questions and to discuss your work confidently. Analyzing and sharing data are important parts of descriptive and experimental research.

26. Experimental Research Design Another way to solve scientific problems is through experimentation. Doing Science 2 Experimental research design answers scientific questions by observation of a controlled situation . Experimental research design includes several steps.

27. 1. Form a Hypothesis (on the right) A hypothesis (hi PAH thuh sus) is a prediction, or statement, that can be tested. Doing Science 2 You use your prior knowledge, new information, and any previous observations to form a hypothesis.

28. 2. Variables In well-planned experiments, one factor, or variable, is changed at a time. Doing Science 2 This means that the variable is controlled. The variable that is changed is called the independent variable . A dependant variable is the factor being measured .

29. Variables To test which of two antibiotics will kill a type of bacterium, you must make sure that every variable remains the same but the type of antibiotic. Doing Science 2 The dependant variable is the growth of the bacteria. In this experiment, the independent variable is the amount or type of antibiotic applied to the bacteria.

30. Variables The variables that stay the same are called constants . Doing Science 2 You cannot run the experiments at two different room temperatures, for different lengths of time, or with different amounts of antibiotics.

31. 3. Identify Controls Your experiment will not be valid unless a control is used. Doing Science 2 A control is a sample that is treated like the other experimental groups except that the independent variable is not applied to it .

32. Identify Controls Doing Science 2 In the experiment with antibiotics, your control is a sample of bacteria that is not treated with either antibiotic. The control shows how the bacteria grow when left untreated by either antibiotic.

33. 4. Number of Trials Experiments done the same way do not always have the same results. Doing Science 2 To make sure that your results are valid, you need to conduct several trials of your experiment. Multiple trials mean that an unusual outcome of the experiment won’t be considered the true result. The more trials you do using the same methods, the more likely it is that your results will be reliable and repeatable.

34. 5. Analyze Your Results When you analyze your results, you can see if your data support your hypothesis. Doing Science 2 If the data do not support your original hypothesis, you can still learn from the experiment. Experiments that don’t work out as you had planned can still provide valuable information. Professional scientists rarely have results that support their hypothesis without completing numerous trials first.

35. 2 Section Check Question 1 Which answers scientific questions through observation? A. descriptive research B. experimental research design C. educated guessing D. hypothesizing NC: 1.05

36. 2 Section Check Answer The answer is A. Descriptive research answers scientific questions through observations while experimental research design is used to answer scientific questions by testing a hypothesis through a series a carefully controlled steps. NC: 1.05

37. 2 Section Check Question 2 What is the first step in solving problems? A. analyze data B. draw conclusion C. form a hypothesis D. identify the problem NC: 1.01

38. 2 Section Check Answer The answer is D. Having a clear understanding of the problem is the first step in problem solving. NC: 1.01

39. 2 Section Check Question 3 A _______ is a prediction or statement that can be tested. Answer The answer is hypothesis. You use your prior knowledge, new information, and any previous observations to form a hypothesis. NC: 1.01