2. Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 1 The Nature of Science Objectives  Describe the main branches of natural science and relate them to each other.  Describe the relationship between science and technology.  Distinguish between scientific laws and scientific theories.  Explain the roles of models and mathematics in scientific theories and laws. Chapter 1

3. Copyright © by Holt, Rinehart and Winston. All rights reserved. How Does Science Take Place?  Science has many branches. Biological science is the science of living things. Physical science is the science of matter and energy. Earth science is the science of the Earth, the atmosphere, and weather.  Science is the knowledge obtained by observing natural events and conditions in order to discover facts and formulate laws or principles that can be verified or tested. Chapter 1

4. Copyright © by Holt, Rinehart and Winston. All rights reserved. Natural Science Section 1 The Nature of Science Chapter 1

5. Copyright © by Holt, Rinehart and Winston. All rights reserved. Biology Section 1 The Nature of Science Chapter 1

6. Copyright © by Holt, Rinehart and Winston. All rights reserved. Physics Chapter 1

7. Copyright © by Holt, Rinehart and Winston. All rights reserved. Earth Sciences Section 1 The Nature of Science Chapter 1

8. Copyright © by Holt, Rinehart and Winston. All rights reserved. How Does Science Take Place?  Science and technology work together. Some scientists practice pure science defined as the continuing search for scientific knowledge. Some scientists and engineers practice applied science defined as the search for ways to use scientific knowledge for practical applications.  Technology is the application of science for practical purposes. Chapter 1

9. Copyright © by Holt, Rinehart and Winston. All rights reserved. Scientific Laws and Theories  Laws and theories are supported by experimental results.  Scientific theories are always being questioned and examined. To be valid, a theory must: explain observations be repeatable be predictable Section 1 The Nature of Science Chapter 1

10. Copyright © by Holt, Rinehart and Winston. All rights reserved. Scientific Laws and Theories,  Scientific law a summary of many experimental results and observations; a law tells how things work  Scientific theory an explanation for some phenomenon that is based on observation, experimentation, and reasoning Chapter 1

11. Copyright © by Holt, Rinehart and Winston. All rights reserved. Comparing Theories and Laws Section 1 The Nature of Science Chapter 1

12. Copyright © by Holt, Rinehart and Winston. All rights reserved. Scientific Laws and Theories,  Mathematics can describe physical events. A qualitative statement describes something with words. A quantitative statement describes something with mathematical equations. Section 1 The Nature of Science Chapter 1

13. Copyright © by Holt, Rinehart and Winston. All rights reserved. Scientific Laws and Theories, continued  Theories and laws are always being tested.  Models can represent physical events. A model is a representation of an object or event that can be studied to understand the real object or event. Scientists use physical and computer models to study objects and events. Section 1 The Nature of Science Chapter 1

14. Copyright © by Holt, Rinehart and Winston. All rights reserved. Models Section 1 The Nature of Science Chapter 1

15. Copyright © by Holt, Rinehart and Winston. All rights reserved. Physical, Mathematical, and Conceptual Models Section 1 The Nature of Science Chapter 1

16. Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 2 The Way Science Works Objectives  Understand how to use critical thinking skills to solve problems.  Describe the steps of the scientific method.  Know some of the tools scientists use to investigate nature.  Explain the objective of a consistent system of units, and identify the SI units for length, mass, and time.  Identify what each common SI prefix represents, and convert measurements. Chapter 1

17. Copyright © by Holt, Rinehart and Winston. All rights reserved. Science Skills  Critical Thinking Scientists approach a problem by thinking logically.  Critical thinking is the ability and willingness to assess claims critically and to make judgments on the basis of objective and supported reasons. Chapter 1

18. Copyright © by Holt, Rinehart and Winston. All rights reserved. Science Skills, continued  Using the scientific method The scientific method is a general description of scientific thinking rather than an exact path for scientists to follow.  Scientific method a series of steps followed to solve problems including collecting data, formulating a hypothesis, testing the hypothesis, and stating conclusions Section 2 The Way Science Works Chapter 1

19. Copyright © by Holt, Rinehart and Winston. All rights reserved. Scientific Method Section 2 The Way Science Works Chapter 1

20. Copyright © by Holt, Rinehart and Winston. All rights reserved. Science Skills, continued  Testing hypotheses Scientists test a hypothesis by doing a controlled experiment. In a controlled experiment, all the factors that could affect the experiment are kept constant except for one change.  Hypothesis a possible explanation or answer that can be tested  Variable a factor that changes in an experiment in order to test a hypothesis Section 2 The Way Science Works Chapter 1

21. Copyright © by Holt, Rinehart and Winston. All rights reserved. Hypothesis Chapter 1

22. Copyright © by Holt, Rinehart and Winston. All rights reserved. Science Skills  Conducting experiments No experiment is a failure The results of every experiment can be used to revise the hypothesis or plan tests of a different variable. Chapter 1

23. Copyright © by Holt, Rinehart and Winston. All rights reserved. Science Skills, continued  Using scientific tools There are many tools used by scientists for making observations, including microscopes telescopes spectroscopes particle accelerators computers Chapter 1

24. Copyright © by Holt, Rinehart and Winston. All rights reserved. Units of Measurement  SI units are used for consistency. Scientists use the International System of Units (SI) to make sharing data and results easier. Chapter 1

25. Copyright © by Holt, Rinehart and Winston. All rights reserved. SI (Le Système Internationale d’Unités) Chapter 1

26. Copyright © by Holt, Rinehart and Winston. All rights reserved. Units of Measurement SI prefixes are for very large and very small measurements.  SI prefixes for large measurements. Chapter 1

27. Copyright © by Holt, Rinehart and Winston. All rights reserved. Units of Measurement  SI prefixes for small measurements. Chapter 1

28. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills Conversions A roll of copper wire contains 15 m of wire. What is the length of the wire in centimeters? 1. List the given and unknown values. Given: length in meters, l = 15 m Unknown: length in centimeters = ? cm Section 2 The Way Science Works Chapter 1

29. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills 2. Determine the relationship between units. Looking at the table of prefixes used for small measurements, you can find that 1 cm = 0.01 m. This also means that 1 m = 100 cm. You will multiply because you are converting from a larger unit (meters) to a smaller unit (centimeters) 3. Write the equation for the conversion. length in cm = m  Section 2 The Way Science Works Chapter 1

30. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills length in cm = 1500 cm 4. Insert the known values into the equation, and solve. length in cm = 15 m  Section 2 The Way Science Works Chapter 1

31. Copyright © by Holt, Rinehart and Winston. All rights reserved. Units of Measurement  Making measurements Many observations rely on quantitative measurements.  Length a measure of the straight-line distance between two points  Mass a measure of the amount of matter in an object  Volume a measure of the size of a body or region in three-dimensional space  Weight a measure of the gravitational force exerted on an object Chapter 1

32. Copyright © by Holt, Rinehart and Winston. All rights reserved. Volume Section 2 The Way Science Works Chapter 1

33. Copyright © by Holt, Rinehart and Winston. All rights reserved. Section 3 Organizing Data Objectives  Interpret line graphs, bar graphs, and pie charts.  Use scientific notation and significant figures in problem solving.  Identify the significant figures in calculations.  Understand the difference between precision and accuracy. Chapter 1

34. Copyright © by Holt, Rinehart and Winston. All rights reserved. Bellringer Imagine your teacher asked you to study how providing different amounts of fertilizer affected the heights of plants. You perform a study and collect the data shown in the table below. Use this data to answer the items that follow. Chapter 1

35. Copyright © by Holt, Rinehart and Winston. All rights reserved. Bellringer 1. Which amount of fertilizer produced the tallest plants? 2. Which amount of fertilizer produced the smallest plants? 3. Plot the data on a grid like the one below. 4. Describe the overall trend as more fertilizer is added to the plants. Chapter 1

36. Copyright © by Holt, Rinehart and Winston. All rights reserved. Presenting Scientific Data  Line graphs are best for continuous change. Line graphs are usually made with the x-axis showing the independent variable and the y- axis showing the dependent variable. The values of the dependent variable depend on what happens in the experiment. The values of the independent variable are set before the experiment takes place. Section 3 Organizing Data Chapter 1

37. Copyright © by Holt, Rinehart and Winston. All rights reserved. Line Graph Section 3 Organizing Data Chapter 1

38. Copyright © by Holt, Rinehart and Winston. All rights reserved. Presenting Scientific Data,  Bar graphs compare items. A bar graph is useful for comparing similar data for several individual items or events. A bar graph can make clearer how large or small the differences in individual values are. Chapter 1

39. Copyright © by Holt, Rinehart and Winston. All rights reserved. Bar Graph Section 3 Organizing Data Chapter 1

40. Copyright © by Holt, Rinehart and Winston. All rights reserved. Presenting Scientific Data  Pie charts show parts of a whole. A pie chart is ideal for displaying data that are parts of a whole. Data in a pie chart is presented as a percent. Chapter 1

41. Copyright © by Holt, Rinehart and Winston. All rights reserved. Writing Numbers in Scientific Notation  Scientific notation is a method of expressing a quantity as a number multiplied by 10 to the appropriate power.  Some powers of 10 and their decimal equivalents are shown below. 10 3 = 1000 10 2 = 100 10 1 = 10 10 0 = 1 10 -1 = 0.1 10 -2 = 0.01 10 -3 = 0.001 Chapter 1

42. Copyright © by Holt, Rinehart and Winston. All rights reserved. Writing Numbers in Scientific Notation,  Using scientific notation When you use scientific notation in calculations, you follow the math rules for powers of 10. When you multiply two values in scientific notation, you add the powers of 10. When you divide, you subtract the powers of 10. Chapter 1

43. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills The adult human heart pumps about 18 000 L of blood each day. Write this value in scientific notation. 1. List the given and unknown values. Given: volume, V = 18 000 L Unknown: volume, V = ? x 10 ? L Chapter 1

44. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills, continued 2. Write the form for scientific notation. V = ? x 10 ? L 3. Insert the known values into the form, and solve. First find the largest power of 10 that will divide into the known value and leave one digit before the decimal point. You get 1.8 if you divide 10 000 into 18 000 L. So, 18 000 L can be written as (1.8 x 10 000) L Section 3 Organizing Data Chapter 1

45. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills, continued Then write 10 000 as a power of 10. Because 10 000 = 10 4, you can write 18 000 L as 1.8 x 10 4 L. Section 3 Organizing Data Chapter 1 V = 1.8 x 10 4 L

46. Copyright © by Holt, Rinehart and Winston. All rights reserved. Scientific Notation Section 3 Organizing Data Chapter 1

47. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills Using Scientific Notation Your state plans to buy a rectangular tract of land measuring 5.36 x 10 3 m by 1.38 x 10 4 m to establish a nature preserve. What is the area of this tract in square meters? 1. List the given and unknown values. Given: length, l = 1.38 x 10 4 m width, w = 5.36 x 10 3 m Unknown: area, A = ? m 2 Section 3 Organizing Data Chapter 1

48. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills, continued 2. Write the equation for area. A = l  w 3. Insert the known values into the equation, and solve. A = (1.38  10 4 m) (5.36  10 3 m) Regroup the values and units as follows. A = (1.38  5.36) (10 4  10 3 ) (m  m) When multiplying, add the powers of 10. A = (1.38  5.35) (10 4+3 ) (m  m) A = 7.3968  10 7 m 2 A = 7.40  10 7 m 2 Section 3 Organizing Data Chapter 1

49. Copyright © by Holt, Rinehart and Winston. All rights reserved. Using Significant Figures Precision and accuracy  Precision the exactness of a measurement  Accuracy a description of how close a measurement is to the true value of the quantity measured  Significant figure a prescribed decimal place that determines the amount of rounding off to be done based on the precision of the measurement Section 3 Organizing Data Chapter 1

50. Copyright © by Holt, Rinehart and Winston. All rights reserved. Accuracy and Precision, part 1 Section 3 Organizing Data Chapter 1

51. Copyright © by Holt, Rinehart and Winston. All rights reserved. Accuracy and Precision, part 2 Section 3 Organizing Data Chapter 1

52. Copyright © by Holt, Rinehart and Winston. All rights reserved. Accuracy and Precision Section 3 Organizing Data Chapter 1

53. Copyright © by Holt, Rinehart and Winston. All rights reserved. Using Significant Figures, continued  When you use measurements in calculations, the answer is only as precise as the least precise measurement used in the calculation.  The measurement with the fewest significant figures determines the number of significant figures that can be used in the answer. Section 3 Organizing Data Chapter 1

54. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills Significant Figures Calculate the volume of a room that is 3.125 m high, 4.25 m wide, and 5.75 m long. Write the answer with the correct number of significant figures. 1. List the given and unknown values. Given: length, l = 5.75 m width, w = 4.25 m height, h = 3.125 m Unknown: Volume, V = ? m 3 Section 3 Organizing Data Chapter 1

55. Copyright © by Holt, Rinehart and Winston. All rights reserved. Math Skills, continued 2. Write the equation for volume. V = l  w  h 3. Insert the known values into the equation, and solve. V = 5.75 m  4.25 m  3.125 m V = 76.367 1875 m 3 The answer should have three significant figures, because the value with the smallest number of significant figures has three significant figures. Section 3 Organizing Data Chapter 1 V = 76.4 m 3

56. Copyright © by Holt, Rinehart and Winston. All rights reserved. Significant Figures Section 3 Organizing Data Chapter 1