2 Chapter: The Nature of Science Table of ContentsChapter: The Nature of ScienceSection 1: The Methods of ScienceSection 2: Standards of MeasurementSection 3: Communicating with Graphs
3 What is Science? 1 Science is a method for studying the natural world. The Methods of Science1What is Science?Science is a method for studying the natural world.It is a process that uses observation and investigation to gain knowledge about events in nature.
4 Major Categories of Science The Methods of Science1Major Categories of ScienceScience can be classified according to three main categories.1) Life science deals with living things.
5 Major Categories of Science The Methods of Science1Major Categories of Science2) Earth science investigates Earth and space.
6 Major Categories of Science The Methods of Science1Major Categories of Science3) Physical science deals with matter and energy.
7 Major Categories of Science The Methods of Science1Major Categories of ScienceSometimes, a scientific study will overlap the categories.One scientist, for example, might study the motions of the human body to understand how to build better artificial limbs.
8 Science Explains Nature The Methods of Science1Science Explains NatureScientific explanations help you understand the natural world.As more is learned about the natural world, some of the earlier explanations might be found to be incomplete or new technology might provide more accurate answers.
9 Science Explains Nature The Methods of Science1Science Explains NatureIn the late eighteenth century, most scientists thought that heat was an invisible fluid with mass.Scientists observed that heat seemed to flow like a fluid. However, the heat fluid idea did not explain everything.
10 Science Explains Nature The Methods of Science1Science Explains NatureIf heat were an actual fluid, an iron bar that had a temperature of 1,000C should have more mass than it did at 100C because it would have more of the heat fluid in it.
11 Science Explains Nature The Methods of Science1Science Explains NatureWhen additional investigations showed no difference in mass, scientists had to change the explanation.
12 The Methods of Science1InvestigationsScientists learn new information about the natural world by performing investigations, which can be done in many different ways.Some investigations involve simply observing something that occurs and recording the observations.
13 The Methods of Science1InvestigationsThe result of these investigations can be either quantitative or qualitative.
14 The Methods of Science1InvestigationsIf a result is quantitative, numbers have been obtained to allow the researcher to arrive at a conclusion.
15 The Methods of Science1InvestigationsIf a result is qualitative, a quality judgment is made by the researcher.For example, students seem happier to have early release Fridays.
16 The Methods of Science1Scientific MethodsAn organized set of investigation procedures is called a scientific method.
17 Steps of the Scientific Method The Methods of Science1Steps of the Scientific MethodIdentify the Problem and form a Problem Question.Form a hypothesis.Perform an experiment to test this hypothesis.Analyze the data.Form a conclusion.
18 The Methods of Science1Forming a HypothesisA hypothesis is a possible explanation for a problem using what you know and what you observe.Some hypotheses can be tested by making observations while others can be tested by building a model and relating it to real-life situations.
19 The Methods of Science1Perform an experimentOne common way to test a hypothesis is to perform an experiment.An experiment tests the effect of one thing on another using controlled conditions.
20 The Methods of Science1VariablesA variable is a quantity that can have more than a single value and can be classified as either independent or dependent.
21 The Methods of Science1VariablesYou might set up an experiment to determine which of three fertilizers helps plants to grow the biggest.Possible variables include plant type, amount of sunlight, amount of water, room temperature, type of soil, and type of fertilizer.
22 The Methods of Science1VariablesIn this experiment, the amount of growth is the dependent variable because its value changes according to the changes in the other variables.PlantAmount of WaterAmount of SunFertilizer TypeHeight after two weeksA4 oz. every three days6hr/day16cmB14cmC18cmDnone10cm
23 The Methods of Science1VariablesThe variable you change to see how it will affect the dependent variable is called the independent variable.PlantAmount of WaterAmount of SunFertilizer TypeHeight after two weeksA4 oz. every three days6hr/day16cmB14cmC18cmDnone10cm
24 Constants and Controls The Methods of Science1Constants and ControlsA factor that does not change when other variables change is called a constant.You might set up four trials, using the same soil and type of plant. Each plant is given the same amount of sunlight and water and is kept at the same temperature. These are constants.
25 Constants and Controls The Methods of Science1Constants and ControlsThe fourth plant is not fertilized.This plant is a control. A control is the standard by which the test results can be compared.PlantAmount of WaterAmount of SunFertilizer TypeHeight after two weeksA4 oz. every three days6hr/day16cmB14cmC18cmDnone10cm
26 Constants and Controls The Methods of Science1Constants and ControlsIf the unfertilized plant grows 1.5 cm, you might infer that the growth of the fertilized plants was due to the fertilizers.PlantAmount of WaterAmount of SunFertilizer TypeHeight after two weeksA4 oz. every three days6hr/day16cmB14cmC18cmDnone10cm
27 The Methods of Science1Analyzing the DataAn important part of every experiment includes recording observations and organizing the test data into easy-to-read tables and graphs.
28 The Methods of Science1Drawing ConclusionsBased on the analysis of your data, you decide whether or not your hypothesis is supported.For the hypothesis to be considered valid and widely accepted, the experiment must result in the exact same data every time it is repeated.
29 The Methods of Science1Being ObjectiveA bias occurs when what the scientist expects changes how the results are viewed.This expectation might cause a scientist to select a result from one trial over those from other trials.
30 Being Objective 1 The experiment must be repeatable. The Methods of Science1Being ObjectiveThe experiment must be repeatable.Findings are supportable when other scientists perform the same experiment and get the same results.
31 Visualizing with Models The Methods of Science1Visualizing with ModelsSometimes, scientists cannot see everything that they are testing.They might be observing something that is too large, too small, or takes too much time to see completely.
32 Visualizing with Models The Methods of Science1Visualizing with ModelsA model represents an idea, event, or object to help people better understand it.
33 The Methods of Science1Models in HistoryLord Kelvin, who lived in England in the 1800s, was famous for making models.To model his idea of how light moves through space, he put balls into a bowl of jelly and encouraged people to move the balls around with their hands.Kelvin’s work to explain the nature of temperature and heat still is used today.
34 The Methods of Science1High-Tech ModelsToday, many scientists use computers to build models.NASA experiments involving space flight would not be practical without computers.
35 High-Tech Models 1 Another type of model is a simulator. The Methods of Science1High-Tech ModelsAnother type of model is a simulator.An airplane simulator enables pilots to practice problem solving with various situations and conditions they might encounter when in the air.
36 Scientific Theories and Laws The Methods of Science1Scientific Theories and LawsA scientific theory is an explanation of things or events based on knowledge gained from many observations and investigations. It is not a guess.Just because a scientific theory has data supporting it does not mean it will never change.
37 Scientific Theories and Laws The Methods of Science1Scientific Theories and LawsA scientific law is a statement about what happens in nature and that seems to be true all the time.Gravity is an example of a scientific law.
38 Scientific Theories and Laws The Methods of Science1Scientific Theories and LawsA theory can be used to explain a law.For example, many theories have been proposed to explain how the law of gravity works.Even so, there are few theories in science and even fewer laws.
39 Using Science—Technology The Methods of Science1Using Science—TechnologyTechnology is the application of science to help people.
40 Using Science—Technology The Methods of Science1Using Science—TechnologyFor example, when a chemist develops a new, lightweight material that can withstand great amounts of heat, science is used.When that material is used on the space shuttle, technology is applied.
41 Using Science—Technology The Methods of Science1Using Science—TechnologyScience and technology do not always produce positive results.The benefits of some technological advances, such as nuclear technology and genetic engineering, are subjects of debate.
42 Question 1 Answer 1 What are the three main categories of science? Section Check1Question 1What are the three main categories of science?AnswerThe three main categories of science are life, earth, and physical.
43 Question 2 Answer 1 What is a common way of testing a hypothesis? Section Check1Question 2What is a common way of testing a hypothesis?AnswerA common way to test a hypothesis is to perform an experiment.
44 Question 3 1 Which of the following is the group in an Section Check1Question 3Which of the following is the group in anexperiment in which all conditions are kept thesame?A. standardB. independent variableC. experimentalD. control
45 Answer 1 The answer is D. Conditions are kept the same Section Check1AnswerThe answer is D. Conditions are kept the samein the control group.