Section 1: The Nature of Science Preview Scientific Thought
Universal Laws Science and Ethics Why Study Science? Summary
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Scientific Thought Scientific thought involves making
observations, using evidence to draw conclusions, being skeptical
about ideas, and being open to change when new discoveries are
made. Scientists carefully observe the world and then ask questions
about what they observe. Scientific thought requires skepticism.
Skepticism is a habit of mind in which a person questions the
validity of accepted ideas. Scientific discoveries can change the
way people view the world.
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Universal Laws Science is governed by truths that are valid
everywhere in the universe. These truths are called universal laws.
Though branches of science address different aspects of the natural
world, universal laws apply to all branches of science and every
person.
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Science and Ethics Ethics are a system of moral principles and
values. Scientific experimentation and discovery can have serious
ethical implications. Because of this, scientific investigations
require ethical behavior. Scientists performing investigations must
report only accurate data, must allow peers to review their work,
and must behave ethically with the people involved in their
investigations.
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Why Study Science? The same critical thinking process that
scientists use is a tool that you can use in your everyday life. An
understanding of science can help you take better care of your
health, be a wiser consumer, and become a better-informed citizen.
You can use science to investigate a problem in your community and
discover helpful solutions. By applying scientific thinking to a
problem, you can help yourself and improve the world around
you.
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Summary Scientific thought involves making observations, using
evidence to draw conclusions, being skeptical about ideas, and
being open to change when new discoveries are made. Science is
governed by truths that are valid everywhere in the universe. These
truths are called universal laws. Scientific investigations require
ethical behavior. An understanding of science can help you take
better care of your health, be a wiser consumer, and become a
better-informed citizen.
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A.The scientist must ensure that the treatment will be
effective. B.The scientist must ensure that the studys results will
not be shared with other scientists. C.The scientist must inform
the volunteers about the potential dangers of participating in the
study. D.The scientist must demonstrate the treatment on him or
herself. 1. A scientist is investigating a new treatment for a
disease that affects thousands of people. Many people with this
disease volunteer to be part of her study. Which of the following
is an ethical concern that the scientist must address before
conducting her study? Test Prep
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Concept Check 1. How can someone practice scientific thought?
2. What are universal laws in science? 3. How do ethics apply to
science? 4. Why should someone who is not planning to become a
scientist study science?
Beginning a Scientific Investigation Most scientific
investigations begin with observations that lead to questions.
Observation is the act of noting or perceiving objects or events
using the senses. To answer a question, scientists first formulate
a hypothesis that leads to scientific investigation. A hypothesis
is a possible explanation that can be tested by observation or
experimentation.
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Visual Concept: Hypothesis
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Scientific Experiments An experiment is a procedure that is
carried out under controlled conditions to test a hypothesis. A
controlled experiment tests one factor at a time and uses a control
group and an experimental group. A control group is a group that
serves as a standard for comparison in an experiment. The
experimental groups are identical to the control group except for
one factor, called a variable.
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Scientific Experiments, continued The single factor that
scientists change in an experiment is called the independent
variable. (do) Factors that may change in response to the
independent variable are called dependent variables. (result)
Scientists analyze changes to the dependent variables in order to
understand how the independent variable affects the system that
they are studying.
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Visual Concept: Controlled Experiment and Variable
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Visual Concept: Independent and Dependent Variables
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Scientific Experiments, continued There are often cases in
which experiments are not possible or not ethical. In these cases,
researchers perform studies. In a study, researchers gather data
about a system by making observations rather than by manipulating
independent variables.
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Scientific Experiments, continued After conducting an
experiment, researchers analyze their results to learn whether the
results support their hypothesis or not. Scientists draw
conclusions that explain the results of their experiments.
Scientists verify their conclusions by conducting their experiments
many times and by checking to see if other scientists have found
similar results.
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Visual Concept: Scientific Method
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Scientific Experiments, continued Every person has his or her
own point of view. A particular point of view is called a bias.
Scientists try to prevent bias from affecting their work, but bias
can still influence an experiment. Sources of funding, personal
involvement in a product, and other conflicts of interest can
affect an experiment. It is wise to view all scientific claims in
their context and think critically about them.
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Scientific Theories In science, a theory is a system of ideas
that explains many related observations and is supported by a large
body of evidence. The main difference between a theory and a
hypothesis is that a hypothesis is a specific, testable prediction
for a limited set of conditions and a theory is a general
explanation for a broad range of data. Constructing a theory often
involves considering contrasting ideas and conflicting
hypotheses.
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Scientific Theories, continued If the results of a scientific
experiment can be reproduced many times, the research may help
develop a new theory. Future research may cause a theory to be
revised or even rejected. By investigating and challenging
theories, scientific understanding grows.
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Summary Most scientific investigations begin with observations
that lead to questions. Scientists can conduct controlled
experiments and perform studies in order to test a hypothesis. The
main difference between a theory and a hypothesis is that a
hypothesis is a specific, testable prediction for a limited set of
conditions, while a theory is a general explanation for a broad
range of data.
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Which of the following is an example of scientific
skepticism?.AA scientist investigates how a universal law affects
many different fields of study. B.A scientist falsely claims to
have discovered a cure for diabetes. C.A scientist conducts an
experiment that supports the conclusions of another scientist. D.A
scientist questions another scientists conclusions and develops an
experiment to test an alternate hypothesis. Test Prep
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Concept Check 1. How do scientific investigations begin? 2.
What are two methods scientists can use to test hypotheses? 3. What
is the difference between a theory and a hypothesis?
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Section 3: Tools and Techniques Preview Measurement Systems Lab
Techniques Safety Summary
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Measurement Systems Measurements taken by scientists are
expressed in the International System of Units (SI), the official
name of the metric system. The International System of Units is
used by all scientists because scientists need to share a common
measurement system. SI is also preferred by scientists because it
is scaled in multiples of 10, which makes the system easy to
use.
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Measurement Systems, continued SI is a decimal system, so all
relationships between SI units are based on powers of 10. Most SI
units have a prefix that indicates the relationship of that unit to
a base unit. For example, the prefix kilo- means 1,000. So, a
kilogram is equal to 1,000 grams.
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Some SI Prefixes
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Bellringer Examine the SI units below. How many meters are
there in a kilometer? How many centigrams are in a gram? How many
milliliters are in 20 liters?
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Metric Units of Lengths and Equivalents
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Lab Techniques In the lab, scientists always keep detailed and
accurate notes and perform precise measurements. Many scientists
also use specialized tools, such as microscopes, and specialized
procedures, such as sterile technique.
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Lab Techniques, continued Scientists use microscopes to view
objects and organisms that are too small to see with the unaided
eye. Sterile technique is a method of keeping unwanted
microorganisms out of a lab in order to minimize the risk of
contamination. Scientists also collect data remotely using devices
such as satellites. These devices help scientists conduct research
that would not have been possible in the past.
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Visual Concept: Types of Microscopes
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Visual Concept: Parts of a Light Microscope
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Safety Scientists must use caution when working in the lab or
doing field research to avoid things like chemical burns, exposure
to radiation, exposure to infectious disease, animal bites, or
poisonous plants. Carefully follow all guidelines and procedures
for working safely in the lab. Know the location and proper
operation of all lab safety equipment. If an accident occurs while
in the lab, remain calm. Make sure you are safe and that no one
else is in danger. Then inform your teacher.
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Summary The International System of Units is used by scientists
because scientists must share a common measurement system. SI is
scaled in multiples of 10, which makes the system easy to use. In
the lab, scientists keep detailed and accurate notes and perform
precise measurements. Scientists also use specialized tools and
procedures. Scientists use caution to avoid hazards such as
chemical burns, exposure to radiation, exposure to infectious
disease, animal bites, or poisonous plants.
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The strength of a light microscope is determined by multiplying
the strength of the eye piece by the strength of the objective
lens. Light microscopes often have several objective lenses.
Suppose a microscope has an eye piece that magnifies by 10, and two
objective lenses, one that magnifies by 10 and one that magnifies
by 40. Calculate the total magnification using both objective
lenses with the eye piece. Test Prep
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Concept Check 1.Why do scientists use SI units for measurement?
2.What are some tools and techniques that scientists use in the
laboratory? 3.What can you do to stay safe during an
investigation?
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Section 4: What Is Biology? Preview The Study of Life
Properties of Life
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The Study of Life Biology is the scientific study of living
organisms and their interactions with the environment. It would be
impossible for one person to become an expert in all aspects of
biology, so scientists specialize. Some of the branches of biology
are biochemistry, ecology, cell biology, genetics, evolutionary
theory, microbiology, botany, zoology, and physiology. Throughout
this course you will learn about each of these branches and have
the opportunity to practice techniques used in careers in each of
these fields.
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Properties of Life All living organisms share certain
properties. The seven properties of life are cellular organization,
homeostasis, metabolism, responsiveness, reproduction, heredity,
and growth. Cellular Organization: All living things are made of
one or more cells. A cell is the smallest unit capable of all life
processes.
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Properties of Life, continued Homeostasis All living organisms
must maintain a stable internal environment in order to function
properly. The maintenance of a stable internal environment in spite
of changes in the external environment is called homeostasis.
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Properties of Life, continued Metabolism Living organisms carry
out different chemical reactions in order to obtain energy. The sum
of all the chemical reactions carried out in an organism is called
metabolism. Almost all of the energy used by living things
originally comes from the sun.
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Properties of Life, continued Responsiveness In addition to
maintaining a stable internal environment, living organisms respond
to their external environment. Can you think of a way that you have
responded to your environment today?
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Properties of Life, continued Reproduction Most living things
can reproduce. Reproduction is the process by which organisms make
more of their own kind from one generation to the next. Heredity
When an organism reproduces, it passes on its own traits to its
offspring in a process called heredity. Inherited characteristics
change over generations. This process is called evolution
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Visual Concept: Heredity Click above to play the video.
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Properties of Life, continued Growth All living organisms grow.
As organisms grow, many change. This process is called development.
Development differs from evolution because development refers to
change in a single individual during that individuals life.
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The Seven Properties of Life 1.Cellular Organization
2.Reproduction 3.Metabolism 4.Homeostasis 5.Heredity
6.Responsiveness 7.Growth & Development
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Summary Branches of biology include biochemistry, ecology, cell
biology, genetics, evolutionary theory, microbiology, botany,
zoology, and physiology. The seven properties of life are cellular
organization, homeostasis, metabolism, responsiveness,
reproduction, heredity, and growth.
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Concept Check What are three of the branches of biology? List
the seven characteristics that all living things share:
Slide 51
Write a short paragraph that expresses your opinion on the
following statement: The lengthy drug- approval process costs
hundreds of lives every year. Doctors have a moral obligation to
provide potentially life-saving drugs to patients with terminal
diseases even if the drugs have not been scientifically
tested.