Chapter 1: The Nature of Science

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Chapter 1 The Nature of Science

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• What is Science?

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What is Science?

• Asking questions about the world around us is
  part of human nature
• There are several ways to explain the world
  around us
• One way is to assume that all events in nature
  have natural causes
• We can then try to arrange a series of
  observations or tests to learn what those causes
  are
• Science is the word that we apply to this process
• The goal of science is to understand the world
  around us
• There are many important fields of study that are
  not considered sciences
• The scientific method helps to distinguish
  science from non-science

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Chapter 1 The Nature of Science

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• The Scientific Method

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The Scientific Method

• The scientific method consists of several steps
• Observing and stating a problem
• Forming a hypothesis
• Testing the hypothesis
• Recording and analyzing data
• Forming a conclusion
• Replicating the work

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Observing and Stating a Problem

• Starts with an observation
• Example leaves changing color in autumn
• As curious scientists, we would then be
  interested in discovering why this color change
  takes place

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Forming a Hypothesis

• We proceed to gather information that helps us
  generate a hypothesis
• A hypothesis is a possible explanation, a
  preliminary conclusion, or even a guess about
  some event in nature
• A hypothesis is usually an ifthen statement
  when in written form

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Testing the Hypothesis

• Next we must test our hypothesis
• Normal testing involves using controlled
  experiments
• Controlled experiments allow researchers to
  isolate and test the effects of a single factor,
  or variable
• The control setup is the setup that remains
  unchanged
• The experimental setup is identical to the
  control setup in every respect except for one

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Recording and Analyzing Data

• When performing experiments it is important to
  keep careful records of observations and
  information, or data
• Most people arrange their data in the form of
  tables and graphs

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Forming a Conclusion

• After viewing the data you should be able to
  develop a conclusion about your hypothesis
• Was it correct?
• If the hypothesis was not correct, it is not
  necessarily a bad experiment, now you just know
  that another factor must be causing the change,
  thus causing you to revise your experiment

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Replicating the Work

• The best scientific experiments can be
  replicated, or reproduced
• It must be possible for either the original
  experimenter or other researchers to duplicate
• If interesting results come from an experiment, a
  researcher will publish a report of the work in a
  scientific journal
• The report must contain enough detail so that
  other scientists can copy the experiment
  precisely to see if the same results continue to
  occur

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Hypotheses and Theories

• When a hypothesis is tested and confirmed often
  enough that it is unlikely to be disproved by
  future tests, it may become worthy of being
  called a theory
• Scientific theories are not just hunches or
  hypotheses
• They are powerful, time-tested concepts that make
  useful and dependable predictions about the
  natural world

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The Scientific Method An Everyday Experience

• Scientists are not the only people who use the
  scientific method
• Auto mechanics
• Plumbers
• Electricians

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A Universal Language The Metric System

• Because most experiments involve measurements,
  researchers need a universal system of
  measurement in which to present their findings
• Scientists use the metric system of length,
  volume, mass, and temperature when describing
  experiments and data
• The metric system is a decimal system based on
  certain standards and scaled on multiples of 10
• Also known as the International System of Units,
  or SI

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Length

• The basic unit of length is the meter (m)
• 1m 39.4in
• Scientists use prefixes to describe measures that
  are smaller or larger than the meter
• centi-
• milli-
• kilo-

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Volume

• Volume is the amount of space an object occupies
• Liter (L) for liquids cubic centimeter (cc, or
  cm3) for solids
• Volume L x W x H

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Mass and Weight

• Mass is a measure of the amount of matter in an
  object
• Weight is a measure of the pull of gravity on
  that mass
• Often used interchangeably
• The basic metric unit scientists use to describe
  mass is the kilogram (kg)
• 1kg 2.2 lbs
• The mass of small objects is measured in grams
  (g)
• 1g 1/1000 kg

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Temperature

• The metric system measures temperature using the
  Celsius scale (oC)
• Water freezes at 0oC and boils at 100oC
• Human body temp 37oC
• Room temperature 21oC

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Chapter 1 The Nature of Science

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• Science Facts and Truth

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Science Facts and Truth

• Scientific knowledge is a constantly changing
  body of observations
• Then Earth was flat, sun revolved around the
  Earth, rain fell through holes in heaven from a
  huge water tank
• Now Earth is round, Earth revolves around the
  sun, rain falls from clouds made of water vapor
• New discoveries are constantly being made
• Without a doubt, some of what you learn this year
  will have to be changed one day

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How to Study Science

• Do not try to memorize the contents of the
  textbook as a list of separate facts
• Arrange facts you need to know in groups
  according to subject
• Work at understanding, rather than just
  memorizing, the topics we talk about
• Remember that science is a process

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Chapter 1 The Nature of Science

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• The Spaceship Called Earth

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The Spaceship Called Earth

• Earlier in human history, the Earth seemed to be
  without end
• There were always new wildernesses to settle, new
  resources for use, and plenty of places to dump
  our garbage
• Now we know there is limited land and limited
  amounts of clean air, water, and other resources
• The Earth is no longer a planet without end. It
  is more like a spaceship with a living cargo,
  carrying limited amounts of supplies