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08.06.14

The Nature of Science

Section 1.1 The Methods of Science

Section 1.2 Standards of Measurement

Section 1.3 Scientific Notation and Dimensional Analysis

Section 1.4 Communicating with Graphs

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Section 1-1

Section 1.1 The Methods of Science

• Identify the common steps of scientific methods.• Compare and contrast types of data.

• Identify types of variables.

• Describe the difference between a theory and a scientific law.

• Compare and contrast science and technology

Investigation: a searching inquiry for ascertaining facts; detailed or careful examination.

Section 1-1

Section 1.1 The Methods of Science (cont.)

Using scientific methods will help you solve problems.

bias

constant

control

dependent variable

experiment

hypothesis

independent variable

model

qualitative data

quantitative data

scientific law

scientific method

technology

theory

Section 1-1

What is Science?

• Science is a method for studying the natural world. It is a process that uses observation (using your senses to gather information) and investigation to gain knowledge about events in nature.

Major Categories of Science

•Earth science investigates Earth and space.

•Physical science deals with matter and energy.

•Life science deals with living things.

• Sometimes, scientifc studies will overlap the categories.

Section 1-1

Science Explains Nature

• Scientific explanations help you understand the natural world.

• Sometimes these explanations must be modified.

− 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.

Section 1-1

InvestigationsScientists learn new information by performing investigations.

•Some investigations involve observing something that occurs and recording the observations.

•Other investigations involve setting up experiments that test the effect of one thing on another. (An experiment is a set of controlled conditions that test the hypothesis.)

•Some involve building a model that resembles something in the natural world and then testing the model to see how it acts.

Section 1-1

Scientific Methods

• The scientific method is a systematic approach used in scientific study, whether it is chemistry, physics, biology, or another science.

• It is an organized set of investigation procedures.

• It is a process that is used to find answers to questions about the world around us. And, it provides methods for scientists to verify the work of others.

Section 1-1

Scientific Methods (cont.)

• Although there is not always the same exact steps in the scientific method, investigations often follow a general pattern.

• The steps in a scientific method are repeated until a hypothesis is supported or discarded.

Section 1-1

• The first step in the scientific method always begins with identification of a problem or a question to be answered based on observations and provides an organized method for conducting an experiment.

• An observation is the act of gathering information (often called data) and leads to a hypothesis. A hypothesis is a tentative explanation for what has been observed.

– Qualitative data is obtained through observations that describe color, smell, shape, or some other physical characteristic that is related to the five senses.

– Quantitative data is obtained from numerical observations that describe how much, how little, how big or how fast.

Scientific Methods (cont.)

Section 1-1

• An experiment tests the effect of one thing on another and usually contains at least two variables.

• A variable is a quantity or condition that can have more than one value.

• Ex. Fertilizer experiment

• An independent variable is the variable you plan to change.

• The dependent variable is the variable that changes in value in response to a change in the independent variable.

Components of an Experiment

Section 1-1

Components of an Experiment (cont.)

• A factor that is not allowed to change when other variables change is called a constant.

• A control is a standard for comparison by which the test results can be compared.

•An inference is a conclusion reached on the basis of evidence and reasoning.

Section 1-1

• Data analysis is the careful and systematic analysis of the data generated in a experiment

• A conclusion is a judgment based on the information obtained from the experiment.

Scientific Methods (cont.)

– A hypothesis is never proven, only supported or discarded.

Section 1-1

• Scientists should also be careful to reduce bias in their experiments. A 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.

• Scientists can lessen bias by running as many trials as possible and by keeping accurate notes of each observation made.

Being Objective

• Valid experiments must have data that are measureable. Why?– This allows others to compare the results to

data they obtain from a similar experiment.

• Most importantly, the experiment must be repeatable.

• Findings are supportable when other scientists perform the same experiment and get the same results.

Being Objective (cont.)

• Sometimes, 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.

Visualizing with Models

Section 1-1

• A model is a verbal, visual, or mathematical explanation of experimental data that can be tested and used to make predictions.

• A model represents an idea, event, or object to help people better understand it.

Visualizing with Models (cont.)

Section 1-1

• A theory is an explanation of things or events based on knowledge gained from many observation and investigations.

• Just because a scientific theory has data supporting it, that does not mean it will never change.

• 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.

Scientific Theories and Laws

• A scientific law is a statement about what happens in nature that is supported by many experiments, and no exceptions to these relationships are found.− Laws tell you what will happen under certain

conditions, but they don’t explain why or how something happens.

– Example of a scientific law...GRAVITY

• A theory can be used to explain a law.

Scientific Theories and Laws (cont.)

• Science can help you explain many things about the world, but science cannot explain or solve everything.– Most questions about emotions and values

are not scientific questions– They CANNOT be tested.

• A survey might predict that you would like a specific piece of art, but science cannot prove that you or others will.

Limitations of Science

Section 1-1

Using Science - Technology

• Science and technology are NOT the same

• Technology is defined as the practical use of scientific information concerned with making improvements in human life and the world around us. It is the application of science to help people.

• Example - developing vs. using

• Technology does not always follow science; sometimes the process of discovery can be reversed.

An Alternative to the Scientific Method?

•Watch the following video and ask yourself whether or not you agree or disagree…why?

•Scientific Method “Stinks”

A. A

B. B

C. C

D. D

Section 1-1

Section 1.1 Assessment

Quantitative data describes observations that are _____.

A. numerical

B. conditions

C. independent

D. hypotheses

A. A

B. B

C. C

D. D

Section 1-1

Section 1.1 Assessment

Scientific methods are _____ approaches to solving problems.

A. dependent

B. independent

C. hypothetical

D. systematic

End of Section 1-1

Section 1-2

Section 1.2 Standards of Measurement

• Name the prefixes used in SI and indicate what multiple of ten each one represents.

• Identify SI units and symbols for time, length, volume, mass, density, and temperature.

• Convert related SI units.

measurement: a method of determining quantity, capacity, or dimension.

Section 1-2

Section 1.2 Standards of Measurement (cont.)

By using uniform standards, nations can exchange goods and compare information easily.

base unit

density

mass

SI

standard

volume

Section 1-2

Units and Standards

• A standard is an exact quantity that people agree to use for comparison.

• Measurements made using the standard can be compared to each other.

• For a measurement to make sense, it must include a number and a unit.

Section 1-2

Measurement Systems

• Système Internationale d'Unités (SI) is an internationally agreed upon system of measurements.

• A base unit is a defined unit in a system of measurement that is based on an object or event in the physical world, and is independent of other units.

• Table 2.1 shows the seven SI base units

Section 1-2

International System of Units

Section 1-2

SI Prefixes

• The SI system is easy to use because it is based on multiples of ten.

• Prefixes are used with the names of the units to indicate what multiple of ten should be used with the units.

• The most frequently used prefixes are shown in table 2.2

Section 1-2

Prefixes Used with SI Units (cont.)

Section 1-2

Converting Between SI Units

• Find the difference between the exponents

of the two prefixes (subtract).

• Start with what you want to find (your final

exponent) then subtract where you started

from (your original exponent)

• Move the decimal that many places.

− Positive difference – move right

− Negative difference – move left

Examples given in class

Section 1-2

Converting Between SI Units

Another way to convert without knowing the exponents

•Remember this saying: Kangaroos have dandruff but don’t care much.

k h da B d c m

kilo hecto deca basic deci centi milli

Examples given in class

Section 1-2

Measuring Distance

• Length is the distance between two points.

• The SI base unit for length is the meter (m), the distance light travels in a vacuum in 1/299,792,458th of a second.

Measuring Volume

• Volume is the amount of space occupied by an object.

• Units for volume include m3, cm3, L, mL

• 1 mL = 1 cm3

Section 1-2

Measuring Matter

• Mass is a measurement of the quantity of matter in an object.

− The SI base unit of mass is the kilogram (kg), about 2.2 pounds

Section 1-2

Measuring Matter

Equations written using the triangle method

•Density = mass/volume

•Mass = density x volume

•Volume = mass/densityDMV

Examples given in class

Section 1-2

Derived Units

• Not all quantities can be measured with SI base units.

• A unit that is defined by a combination of base units is called a derived unit.

− Density is a derived unit.

• A unit multiplied by itself is also a derived unit.

− m3 is a derived unit.

Section 1-2

Measuring Time

• Time is the interval between two events.

• The SI base unit of time is the second (s), based on the frequency of radiation given off by a cesium-133 atom.

Section 1-2

Measuring Temperature

• The SI base unit of temperature is the kelvin (K).

• Zero kelvin is the point where there is virtually no particle motion or kinetic energy, also known as absolute zero.

• Absolute zero = -273 °C

• Two other temperature scales are Celsius and Fahrenheit.

Section 1-2

Relationships Between the Temperature Scales

• Kelvin temperature scale

K = °C + 273

• Two other temperature scales are Celsius and Fahrenheit.

°F = 1.8(°C ) + 32

°C = (°F – 32)/1.8

A. A

B. B

C. C

D. D

Section 1-2

Section 1.2 Assessment

Which of the following is a derived unit?

A. yard

B. second

C. liter

D. kilogram

A. A

B. B

C. C

D. D

Section 1-2

Section 1.2 Assessment

What is the relationship between mass and volume called?

A. density

B. space

C. matter

D. weight

End of Section 1-2

Section 1-3

Section 1.3 Scientific Notation and Dimensional Analysis

• Express numbers in scientific notation.

• Convert between units using dimensional analysis.

quantitative data: numerical information describing how much, how little, how big, how tall, how fast, and so on.

Section 1-3

Section 1.3 Scientific Notation and Dimensional Analysis (cont.)

conversion factor

dimensional analysis

scientific notation

Scientists often express numbers in scientific notation and solve problems using dimensional analysis.

Section 1-3

Scientific Notation

• Scientific notation can be used to express any number as a number between 1 and 10 (the coefficient) multiplied by 10 raised to a power (the exponent).

• Count the number of places the decimal point must be moved to give a coefficient between 1 and 10.

Section 1-3

Scientific Notation (cont.)

800 = 8 102

0.0000343 = 3.43 10–5

Examples given in class

• The number of places moved equals the value of the exponent.

• The exponent is positive when the decimal moves to the left and negative when the decimal moves to the right.

Section 1-3

Calculating with Scientific Notation

• Addition and subtraction

– Exponents must be the same.

– Rewrite values with the same exponent.

– Add or subtract coefficients.

Section 1-3

Calculating with Scientific Notation (cont.)

• Multiplication and division

– To multiply, multiply the coefficients, then add the exponents.

– To divide, divide the coefficients, then subtract the exponent of the divisor from the exponent of the dividend.

Section 1-3

Dimensional Analysis

• Dimensional analysis is a systematic approach to problem solving that uses conversion factors to move, or convert, from one unit to another.

• A conversion factor is a ratio of equivalent values having different units.

• If a conversion factor is expressed as a fraction, then it has a value of 1.

• Multiplying a quantity by 1 does not change the value of the quantity.

Section 1-3

Dimensional Analysis (cont.)

• Using conversion factors

– A conversion factor must cancel one unit and introduce a new one.

Examples given in class

A. A

B. B

C. C

D. D

Section 1-3

Section 1.3 Assessment

What is a systematic approach to problem solving that converts from one unit to another?

A. conversion ratio

B. conversion factor

C. scientific notation

D. dimensional analysis

A. A

B. B

C. C

D. D

Section 1-3

Section 1.3 Assessment

Which of the following expresses 9,640,000 in the correct scientific notation?

A. 9.64 104

B. 9.64 105

C. 9.64 × 106

D. 9.64 610

End of Section 1-3

Section 1-4

Section 1.4 Communicating With Graphs

• Identify three types of graphs explain the ways they are used.

• Distinguish between dependent and independent variables.

• Analyze data using the various types of graphs.

Graphs visually depict data, making it easier to see patterns and trends.

data: a series of observations, measurements, or facts; information.

graph

Section 1-4

Graphing

• A graph is a visual display of data that makes trends easier to see than in a table.

Section 1-4

Graphing (cont.)

• A circle graph, or pie chart, is used to show how some fixed quantity is broken down into parts.

Section 1-4

Graphing (cont.)

• Bar graphs are useful for comparing information collected by counting.

Section 1-4

Graphing (cont.)

• A line graph can show any relationship where the dependent variable changes due to changes in the independent variable.

• Line graphs often show how a relationship between variables changes over time.

• You can show more than one event on the same graph as long as the relationship between the variables is identical.

Section 1-4

Graphing (cont.)

• On line graphs, independent variables are plotted on the x-axis and dependent variables are plotted on the y-axis.

Section 1-4

• If a line through the points is straight, the relationship is linear and can be analyzed further by examining the slope.

Graphing (cont.)

Section 1-4

• Interpolation is reading and estimating values falling between points on the graph.

• Extrapolation is estimating values outside the points by extending the line.

Interpreting Graphs

Section 1-4

• This graph shows important ozone measurements and helps the viewer visualize a trend from two different time periods.

Interpreting Graphs (cont.)

A. A

B. B

C. C

D. D

Section 1-4

Section 1.4 Assessment

____ variables are plotted on the ____ axis in a line graph.

A. independent, x

B. independent, y

C. dependent, x

D. dependent, z

A. A

B. B

C. C

D. D

Section 1-4

Section 1.4 Assessment

What kind of graph shows how quantities vary across categories?

A. pie charts

B. line graphs

C. Venn diagrams

D. bar graphs

End of Section 1-4

Resources Menu

ODE Requirements

Study Guide

Chapter Assessment

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Study Guide 1

Section 1.1 The Methods of Science

Key Concepts

• Science is a way of learning about the natural world through investigation.

• Scientific methods are systematic approaches to problem solving.

• Scientific investigations can involve making observations, testing models, or conducting experiments.

• Scientific experiments investigate the effect of one variable on another. All other variables are kept constant.

Study Guide 1

Section 1.1 The Methods of Science

Key Concepts

• Qualitative data describe an observation; quantitative data use numbers.

• Independent variables are changed in an experiment. Dependent variables change in response to the independent variable.

• Scientific laws are repeated patterns in nature. Theories attempt to explain how and why these patterns develop.

• A theory is a hypothesis that is supported by many experiments.

Study Guide 1

Section 1.1 The Methods of Science

Key Concepts

Study Guide 2

Section 1.2 Standards of Measurement

Key Concepts

• A standard of measurement is an exact quantity that people agree to use as a basis of comparison.

• When a standard of measurement is established, all measurements are compared to the exact quantity – the standard. Therefore, all measurements can be compared with one another.

• The most commonly used SI units include: length – meter, volume – liter, mass – kilogram, and time – second.

• In SI, prefixes are used to make the base units larger or smaller by multiples of ten.

Study Guide 2

Section 1.2 Standards of Measurement

Key Concepts

• SI measurement units allow scientists to report data to other scientists.

• Any SI unit can be converted to any other related SI unit by multiplying by the appropriate conversion factor.

• To convert to Kelvin temperature, add 273 to the Celsius temperature. K = °C + 273

• Volume and density have derived units. Density, which is a ratio of mass to volume, can be used to identify an unknown sample of matter.

Study Guide 3

Section 1.3 Scientific Notation and Dimensional AnalysisKey Concepts

• Scientific notation makes it easier to handle extremely large or small measurements.

• Numbers expressed in scientific notation are a product of two factors: (1) a number between 1 and 10 and (2) ten raised to a power.

• Numbers added or subtracted in scientific notation must be expressed to the same power of ten.

• When measurements are multiplied or divided in scientific notation, their exponents are added or subtracted, respectively.

Study Guide 3

Section 1.3 Scientific Notation and Dimensional Analysis (cont.)Key Concepts

• Dimensional analysis often uses conversion factors to solve problems that involve units. A conversion factor is a ratio of equivalent values.

Study Guide 4

Section 1.4 Communicating with Graphs Key Concepts

• Bar graphs are used to show data collected by counting. Bar graphs show how a factor varies with time, location, or temperature.

• Circle graphs show how a fixed quantity can be broken into parts. Circle graphs show parts of a whole.

• Line graphs show continuous changes among related variables. In a line graph, the independent variable is always plotted on the horizontal x-axis. The dependent variable is always plotted on the vertical y-axis.

Study Guide 4

Section 1.4 Communicating with Graphs (cont.)Key Concepts

• Independent (x-axis) variables and dependent (y-axis) variables can be related in a linear or a nonlinear manner. The slope of a straight line is defined as rise/run, or ∆y/∆x.

• Because line graph data are considered continuous, you can interpolate between data points or extrapolate beyond them.

A. A

B. B

C. C

D. D

Chapter Assessment 3

Which of the following would be an example of quantitative data?

A. blue socks

B. square peg

C. six kilograms

D. loud noise

A. A

B. B

C. C

D. D

Chapter Assessment 4

Which of the following is an example of qualitative data?

A. 1.35 kilograms

B. red flower

C. eight pieces

D. three kilometers

A. A

B. B

C. C

D. D

STP 1

_____ is/are anything that has mass and takes up space.

A. Solids

B. Building block

C. Forces

D. Matter

A. A

B. B

C. C

D. D

STP 2

Which type of variables are controlled by the scientist?

A. independent

B. dependent

C. pure

D. response

A. A

B. B

C. C

D. D

STP 5

Which of the following describes a systematic approach to solving problems?

A. pure research

B. hypothetical method

C. theoretical method

D. scientific method

End of Custom Shows

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