1. The Nature of Science Chapter 1 Sections 1 - 3

2. Chp 1 – The Nature of Science  Section 1- The Methods of Science slides 3 – 28 slides 3 – 28slides 3 – 28  Section 2- Standards of Measurement  slides 29 -50 slides 29 - slides 29 -  Section 3 – Communicating with Graphs slides 51-67 slides 51-67

3. 1 – The Methods of Science  How scientists solve problems  Why scientists use variables  Compare and contrast science and technology

4. What is science?

5. What are the major categories of science?  Life Science-  Earth Science-  Physical Science-  Sometimes these three categories overlap.

6. What are the major categories of science?  Life Science- the study of living things  Earth Science- the study of Earth & outer space  Physical Science- the study of matter & energy  Sometimes these three categories overlap.

7. How does science explain nature?  Scientists use investigations to get new information about the natural world.  Technology helps scientists learn more.  Sometimes new info causes scientific explanations to change.

8. What are investigations?  1. Observing & recording  2. Experimenting  3. Building a model  Scientists might use one or all three types of investigations to get new information about how nature works.

9. What is a variable?  An experiment might test 3 fertilizers to see which one helps plants grow biggest. In this experiment there are 2 variables being studied. A variable is a quantity that can have more than one value. The height of the plants is a variable because it can have a range of values. The variable that is measured at the end of the experiment is called the dependent variable because it depends upon what happens in the experiment.

10. What is a variable?  The height of the plants is the dependent variable because that is what is measured at the end of the experiment.  The fertilizer is also a variable because the researcher is using three different kinds.  A variable that is controlled and changed by the researcher is called the independent variable. There should be only one independent variable in an experiment.  

11. Why are constants & controls important?  To keep an investigation fair, all other factors must remain the same for each trial. A factor that does not change is a constant.  In the fertilizer experiment, the constants are the amount of water & sunlight the plants get & the kind of soil they’re planted in. All constants are kept the same for the three types of fertilizer tested.

12. Why are constants & controls important?  Researchers use a control to compare the results of the experiment against. The control plant does not receive any fertilizer but receives the same amount of water & sunlight & soil as the other plants.  This helps scientists understand whether the fertilizer is having an effect on the plants or whether they would grow that way in regular conditions.

13. Scientific Methods  A set of steps used by scientists in an investigation is called a scientific method. Sometimes certain steps may be repeated & others may be skipped. The steps are cyclical & may be started at any point.

14. State the problem:  Many investigations begin when someone sees something happen in nature & wonders how or why it happened.  Sometimes a question is asked because you are looking for a better way.

16. Research & Gather Information  Study the problem before doing any testing. Find information regarding similar designs or problems. Using your research and what you’ve observed, form a hypothesis.

17. Form a hypothesis  A hypothesis is an explanation for a question or problem based on what you know & what you observe.  It must be tested to be certain whether or not it works.

18. Test the hypothesis  Some hypotheses are tested by making observations or by building a model. Often an experiment is used to test the hypothesis. The experiment looks at how one thing affects another under controlled conditions.

19. Analyze Data  All results and observations must be recorded during an experiment.  Many important discoveries have been made from unexpected results.  The information or data should be organized into an easy-to-read table or graph.

20. Draw Conclusions  Scientists share their data with others. If the data supports the hypothesis and can be repeated successfully, other people will eventually agree with the conclusions. Sometimes data does not support the original hypothesis.

21. Why must scientists be objective?  Bias occurs in an experiment when a scientist expects something to happen & lets this influence how the results are viewed.  Bias can be reduced by doing the experiment over many times while keeping careful notes. Other scientists repeat the same experiment to see if they get the same results.

22. Visualizing with Models  If a scientist is studying something that is too big or too small or will take too long to see completely, they use a model.  A model represents an idea, an event, or an object. It helps people understand how & why things happen.  Some models are accepted and some such as the geocentric model shown here are later disproved by evidence.

23. What are high-tech models?  Computer models can be used to solve difficult mathematical equations.  A simulator can be used to create the same kind of conditions found in real life. For example, a flight simulator is a model of an airplane that can help a pilot test different ways to solve a problem without endangering himself or the plane.

24. Scientific Theories & Laws  A scientific theory is a way of explaining things or events based on what has been learned from many observations and investigations that have been repeated many times. New information in the future may change the theory.  A scientific law is a statement about what happens in nature all the time. It explains what will happen under certain conditions but not why or how it happens. Gravity is a scientific law.

25. Limitations of Science  Science cannot explain everything such as questions about emotions or values. A survey of peoples’ opinions would not prove that everyone believes the same.  Scientists make predictions when they perform experiments which test and verify whether they are right by using a scientific method.

26. Using Science- Technology  Technology is the application of science.  For example, science is used when a chemist develops a new material. When this new material is used on the space shuttle, technology is applied.  Not all technology is good. Some people question the benefits of certain technology. Society must make decisions about these issues. Learning more about science can help you do that.

27. Put the steps for scientific method in order: Analyze the data Test the hypothesis State the problem Draw conclusions Gather information Form a hypothesis

28. Put the steps for scientific method in order: Gather information Form a hypothesis Analyze the data Draw conclusions State the problem Test the hypothesis

29. 2 – Standards of Measurement  What You’ll Learn:  SI Units and symbols for length, volume, mass, density, time, and temperature  How to convert related SI units

30. 2 - Standards of Measurement  A standard is an exact quantity that people agree to use to compare measurements.  It is always the same quantity no matter where it is used in the world.  

31. Measurement Systems  A measurement is a way to describe the world using numbers answering questions such as how much, how long or how far.  For a measurement to make sense, it must include a number and a unit.  The U.S. commonly uses English units such as inches, feet yards, miles, gallons and pounds.  Most nations use the metric system which is based on multiples of ten.

32. What is the International System of Units?  This system is abbreviated from the French Le Systeme Internationale d’ Unites.  The SI standards are accepted and used by scientists all over the world.  The table shows the names & symbols for the 7 base units.

33. What are SI prefixes? PrefixSymbolMultiplication factor petaP10 15 teraT10 12 gigaG1 000 000 00010 9 megaM1 000 00010 6 kilok100010 3 hectoh10010 2 dekada1010 1 decid0.110 -1 centic0.0110 -2 millim0.00110 -3 microµ0.000 00110 -6 nanon0.000 000 00110 -9  The SI system is easy to use because it is based on multiples of ten.  A prefix is added to the name of a base unit to indicate how many multiples of ten it includes.  1 kilogram = 1000grams SI prefixes:

34. How do you convert between SI units?  Sometimes quantities are measured using different units so they must be converted to similar units by using a conversion factor.  new unit = 1000 mL  Old unit 1L  1.3 L X 1000mL/ 1L= 1,300mL  A length of rope measures 3,000 mm. How long is it in meters?

35. Measuring Distance  Length measures the distance between two points. The SI unit for length is the meter, about the length of a baseball ball or longer than a yardstick.

36. How do you choose a unit of length?  The unit you choose depends upon the object being measured. By choosing the best unit you can avoid very large or very small numbers.  Length of classroom would be measured in meters while the distance from school to your house would be measured in kilometers.

37. Measuring Volume  Volume is the amount of space an object fills. The volume of a rectangular solid such as a brick is found by multiplying its length, width and height (V= l x w x h) thus units must be expressed as cubic or to the third power. (m 3 )

38. How do you measure the volume of liquid?  Liquids do not have “sides” so measuring their volume requires a container with known capacity.  Common units for expressing liquid volume are liters, L and mL or milliliters.  1 mL= 1 cm 3  1 L= 1000 cm 3  How do we KNOW this?

39. Measuring Matter  Mass is a measure of how much matter is in an object.  A golf ball and a table tennis ball are about the same size, but the first has more matter, or mass, than the other.

40. What is density?  Density of an object is the amount of mass in one cubic unit of volume of the object.  Find density by dividing an object’s mass by its volume.  D= m/V  How do we KNOW what we know? know?

41. Measuring Time  Sometimes scientists need to know how long it takes for something to happen.  The SI unit of time is second, s, measured with a clock or stopwatch. Jantar Mantar is the biggest of five astronomical observatory build by Maharaja Jai Singh during the period 1727-1734 in north India. The observatory consists of fourteen major geometric devices (or yantra in Hindi) for measuring time, predicting eclipses, etc. The Samrat Jantar, the largest instrument, is 90 feet high, its shadow carefully plotted to tell the time of day.

42. Measuring Temperature  Sometimes you need to measure how much something heats up or cools down.  Temperature is a measure of how hot or cold something is.

43. What is Fahrenheit?  The Fahrenheit scale is based on the temperature of the human body, 98.6°F.  On this scale, water freezes at 32°F and boils at 212°F.

44. What is Celsius?  Scientists use the Celsius scale to measure temperature.  On this scale, water freezes at 0°C and boils at 100°C.  The scale is divided into 100 equal degrees between freezing and boiling.

45. What is Kelvin?  The SI unit for measuring temperature is Kelvin, K.  0 K is called absolute zero, the coldest possible temperature = -273°C.  Divisions on K & C scales are equal so to convert to K, add 273 to C.

46. SI Base Unit LengthTime is Kilogram Kelvin for

47. SI Base Unit LengthTime is MeterKilogram Kelvin for

48. SI Base Unit LengthMassTime is MeterKilogram Kelvin for

49. SI Base Unit LengthMassTime is MeterKilogram SecondKelvin for

50. SI Base Unit LengthMassTimeTemperature is MeterKilogram SecondKelvin for

51. 3 – Communicating with Graphs  What You’ll Learn:  How graphs are used  How to distinguish between dependent and independent variables

52. A Visual Display  A graph is a visual display of information or data.  Scientists often use graphs to display results of their experiments.  Patterns in the data show better in a graph than if the data were listed in a table.  The most common types are line, graph or bar graphs. Each type is used to display different types of data.

53. Line Graphs  Line graphs show change over time.  It can show more than one event on the same graph.  Horizontal or x-axis always used for the independent variable.  Vertical or y-axis used for the dependent variable.

54. Line Graphs  Select a scale that makes your graph sensible & readable. Spread out the information.  Plot data points (x,y) then draw a line to connect the points.  All data must use the same units.

55. Using Excel to graph  In the A column enter your x data; in the B column enter your y data.  Go to chart wizard on the tool bar; choose XY (scatter), then next. It will set your range in step 2.

56. Excel Graphing  In step 3, you enter the chart title and the name & unit on the X & Y axis as shown.  Finish step 4, then right click on a data point to add a trend line. To save ink, right click one the gray area & click clear.

57. Excel Graphing  Under Format trend line, choose options & check the bottom two options to add the equation & correlation of the line.  Excel allows you to quickly and easily create accurate graphs with your data.

58. The equation may be rewritten to clarify the relationship between position and time. Position in meters equals 7.5 times time in seconds plus five. The slope of the line (m) equals rise over run (15/2) or 7.5 and the y-intercept is 5.

59. Bar Graphs  Bar graphs are useful for comparing data collected by counting. Each bar shows a number counted at a particular time.  Again, the independent variable is plotted on the x-axis, & the dependent variable is on the y-axis.  The data are not related so the bars do not touch.

60. Circle Graphs  A circle or pie graph is used to show how a certain quantity is broken down into parts.  The circle represents the whole and the segments are parts or percentages of the whole.

61. Graphs May be To show

62. Graphs May be To show Line

63. Graphs May be To show LineBar

64. Graphs May be To show LineBar Circle

65. Graphs May be To show LineBar Circle Trends or change over time

66. Graphs May be To show LineBar Circle Trends or change over time Information collected by counting

67. Graphs May be To show LineBar Circle Trends or change over time Information collected by counting Proportional parts of a whole