Name
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Date
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Measurement-A Common Language
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Why Do Scientists Use a Standard Measurement System?
Standard measurement
allows scientists
of the metric system called the International
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of Units, or SI. Using SI as the standard system
everywhere to repeat experiments. In the 1790's,
scientists in France developed a system of
measurement called the metric system. The
metric system is a system of measurement based
of measurement allows scientists to compare
data and communicate with each other about
their results.
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What Are Some SI Units of Measure?
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In the 51system, the basic unit for measuring
lenoth is the meter em). For lencths smaller than a
sides. Use cubic meters to measure the volume of
solids. To measure the volume of a liquid, use the liter
(U, and read the level at the bottom of the meniscus,
or curve. To measure the volume of an irreuular solid,
use the displacement method: immerse the obiect in
water and measure how much the water level rises.
meter, the centimeter (em) and millimeter (mm) are
used. The kilometer (km) is used for measurinq lone
distances.
Mass is a measure of the amount of matter in
an obiect. A balance is used to measure mass bv
comoarinc the mass of an obiect to a known mass.
Densitv, a measure of how much mass is contained
in a qiven volume, is expressed as a relationship
In SI svstem, the basic unit for measurinq mass
is the kilouram (ko). To measure smaller masses
between two units. In 51,the basic unit for
measurina densitv is kiloarams per cubic
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arams (a) and milliarams (me) are used. Unlike mass
weight is a measure of the force of oravitv actinc on.
In addition to the Celsius scale, scientists
sometimes use another temoerature scale, called
the Kelvin scale. In fact, the Kelvin (K) is the
official 51 unit for temperature. A thermometer is
used to measure temperature. The second Is) is the
51unit used to measure time.
an object. A scale is used to measure weioht.
Volume is the amount of space an obiect or
substance takes up. In 51,the basic unit for
measurino volume is the cubic meter (m3).A cubic"
meter is equal to the volume of a cube with 1-meter
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On a separate sheet of paper, tell why scientists in different countries can easily compare
the amount of matter in similar objects in their countries.
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ALL RIGHTS
RESERVED.
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Name
Date
--------------------------------------
-------------
Class
--------------
Mathematics and Science
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What Math Skills Do Scientists Use?
Math skills that scientists use to collect data
include estimation, accuracy and precision,
and siqnificant
fiuures. An estimate is an
of measurements are to each other. A reliable
measurement is both accurate and precise.
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Scientists use certain math tools to analyze
data. These tools include calculating percent
error; finding the mean, median, mode,
and ranee: and checkina the reasonableness
of data.
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The mean is the numerical averace of a set of
data. The median is the middle number in a set of
data. The mode is the number that appears most
often in a list of numbers. The ranee of a set of data
is the difference between the qreatest value and the
least value in the set.
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how accurate an experimentalvalue
is. A low
percent error means.the resultvou obtained was
accurate. A high per(errterror'means
your result
An important part of analvzino any set of data is
to ask, "Are these data reasonable? Do they make
sense?" Data that do not fit with the rest of a data set
was not accurate.
are anomalous data.
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On a separate sheet of paper, summarize the math skills and tools scientists
use in their work.
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Percent error calculations are awav to determine
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What Math Tools Do Scientists Use?
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measurements your answer can onlv have as many
places after the decimal as the measurement with
the fewest places after the decimal. When you
multiply measurements the answers should on Iv
have the same number of siqnificant fiqures as the
measurement with the fewest siqnificant fiqures.
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In science the words eccurecv and precision
have different rneaninos. Accuracv refers to how
dosea measurement is to the true or accepted
value. Precision refers to how close a orouo
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measurement inc Iude a II d ioits measure d exactiv.
plus one estimated digit. When you add or subtract
numbers. They may base an estimate on indirect
measurements calculations models, or a sample.
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Significant figures communicate how precise
measurements are. The significant figures in a
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of a number based on reasonable
'assumptions,
It is not a guess. Scientists often;
rely on estimates w h en they cannot 0btain exact
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Name
Date
Class
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Graphs in Science
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What Kinds of Data Do Line Graphs Display?
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Scientists control changes in the manipulated
variable. Then they collect data about how the
responding variable changes. A line graph is
used when a manipulated variable is continuous,
which means there are other points between
the tested ones.
To help see what data mean you can use a graph.
A graph is a "picture" of your data. One kind of
graph is a line graph. Line graphs display data
that show how one variable (the responding
variable) changes in response to another
variable (the manipulated variable).
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Why Are Line Graphs Powerful Tools?
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A line qraph in which the data points vield a
straiaht line is a linear graph. The kind of qraph in
which the data points do not fall alonq a straioht
line is called a nonlinear oranh. Both kinds of
line oraohs are useful. Line qraphs are powerful
tools in science because they allow you to
identify trends, make predictions,
anomalous data.
and recoqnize
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Graphs make it easv to see anomalous data points.
When a oraoh does not have any clear trends, it
probably means that the variables are not related.
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On a separate sheet of paper, explain what line graphs show and how they
help scientists.
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91C
ALL RIGHTS RESERVED.
Name -----------------------------------
Date ------------ Class -------------
Models as Tools in Science
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They use models as representations of things that are
either very large, such as Earth's core, or very small,
such as an atom: These are physical models. Other
models, such as mathematical equations or word
descriptions, are models of processes.
In science, a model is any representation of an object
or process. Pictures, diagrams, computer programs,
and mathematical equations are all examples
of scientific models. Scientists use models to
understand things they cannot observe directly.
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What Is a System?
is what happens in a svstem. Outout is the material
or enerov that comes out of a system. Some systems
also have feedback, output that chances the system
in some way.
A system is a croup of parts that work toqether
to oerform a function or oroduce a result. All
systems have input, process, and output. Input is the
material or enerov that qoes into a system. Process
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It's easy to identify the inputs and outputs of
a system. It's not so easyto observe a system's
process. Scientists use models to understand
how systems work. They also use models
to predict chances in a system as a result
of feedback or input changes. However, they
keep in mind that predictions based on models are
uncertain.
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When scientists construct a model of a system, they
beoin with certain assumptions. These assumptions
allow them to make a basic model that accurately
reflects the parts of the system and their relationships.
A food chain is a qood model of a simple system to
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beqin to understand how enerqy moves throuqh livinq
thincs in an environment. However, it shows how only
a few of those livinq thinqs are related. So a scientist
may build a food web to model a more complete
picture of the system.
Some systems that scientists study are complex. Many
parts and many variables interact in these systems.
So scientists may use a computer to keep track of all
the variables. Becausesuch systems are difficult to
model, scientists may model only the specific parts of
the system thev want to study. Their model may be
used to show the processesin the system or to make
predictions .
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sheet of paper, explain how models and systems are related in science.
COPYRIGHT
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OR ITS AffiLIATES.
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ALL RIGHTS RESERVED,
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Name
------------------------------------
Date
----------
Class
-------------
Safety in the Science Laboratory
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You must prepare before you begin a scientific
or lab. Good preparation helps you
Read throuah any procedures carefullv. and make
sure you understand all the directions. If anvthino is
unclear, ask your teacher about it before you begin
the lab. Lab instructions may include safety svrnbols.
Safety svmbols alert you to possible sources of
accidents in an investiqation.
The most important
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shoes. Wear heat-resistant cloves when handline
hot objects and plastic qloves when handlinq
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animals, plants, or chemicals. Handle live animals
and plants with care. Make sure electric cords are
untangled and out of th~
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When you have completed a lab, be sure to
clean up your work area. Turn off and unpluc
any ecuioment. Dispose of any waste materials
properly~ Follow your teacher's instructions
about proper disposal. Finallv, be sure to wash
safety rule is simple: Always
follow your teacher's instructions and the directions
exactly. When performinq a lab keep your work
your hands thorouohlv
area clean and oraanized. Label all containers so yOU
do not use the wronq chemical accidentally. Also
do not rush throuah any of the steos. Move slowlv
and carefullv around the room. Finallv, alwavs show
resoect and courtesy to your teacher and classmates.
after workinq
in the
laboratorv.
Some of vour science investiaations will be
done in the field, or any area outside a science
laboratorv. Good preparation helps you stay safe
in the field. Alwavs tell an adult where
be. Never carry out a field investiqation
Wear safetv aoaales to Protect your eves. Wear
an apron to protect your body and clothes from
will
alone.
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chemicals. Tie back Ion a hair. Wear closed-toe
stay safe when doing science investigations.
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Why Prepare For an Investigation?
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When any accident occurs no matter how minor
tell vour teacher immediatelv. Then listen to
your teacher's directions and carry them out
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Proper use of all the emeraencv eouiornent in your
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On a separate sheet of paper, explain how to prepare for a scientific investigation as well
as what to do should an accident occur during one.
COPYRIGHT
©
BY PEARSON
EDUCATION
INC.,
OR ITS AFFILIATES.
105C
ALL RIGHTS
RESERVED.
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