Chapter Introduction
Lesson 1
Nature of
Science
Lesson 2
The Scientific
Method
Lesson 3
Tools of the
Scientist
Chapter Wrap-Up
How do scientists
perform scientific
investigations?
The Nature of Science
Essential Question
• What do scientists do?
The Nature of Science
Science
Observation
Inference
Independent
variable
Dependent
variable
Controlled
experiment
Scientific theory
Model
Technology
Scientific law
What is Science?
• Science is a way of learning about the
natural world that provides possible
explanations to questions.
• Scientists ask questions about the natural
world (why, how or when) and try to
answer those questions using evidence
they gather.
• This process is called scientific inquiry.
What are the branches of science?
• Science if often divided into three
branches:
– Physical science, or physics and
chemistry, is the study of matter and
energy.
– Earth Science is the study of Earth and
space including processes that occur on
Earth and deep within Earth.
– Life Science is the study of living things.
What is Science? (cont.)
• Scientific inquiry often starts with an
observation about the natural world.
• Observation is using one or more of
your senses (sight, touch, sound,
taste, and smell) to identify or learn
about something.
• Example: Brandon is wearing a red
shirt.
What is Science? (cont.)
• Observations lead to questions.
– Observation: shorter days in winter
– Question:
Why?
– Answer: investigate to find answer
What is Science?
(cont.)
• Science can answer a question only
with the information available at the
time.
• Sometimes the answers to scientific
questions are inferred.
What is Science?
(cont.)
• An inference is a conclusion formed
from available information or evidence.
– Ex. Knowing the Earth is tilted, you might
infer that the days are shorter in the winter
because the Earth is tilted away from the
sun during this time.
– Example: Briggs coughed, he might have
a cold.
What is Science?
OBSERVATION
(cont.)
INFERENCE
Ms. Crane poured water into a cup.
The water disappeared by
evaporation.
The glass graduated cylinder has a
white ring at the top.
The ring is at the top to prevent
breakage in case it falls.
More students are wearing red shirts
than white shirts
Red shirts are easier to keep clean
than white shirts.
Tree branches are on the front lawn.
The tree branches were probably
blown out of the trees by the wind.
What are types of data? (cont.)
• Description is a summary of
observations.
– Scientists use different types of data,
including descriptions, to develop
explanations.
• Explanation is an interpretation of
observations.
What is Science?
(cont.)
• Any answer to a scientific question is uncertain
because people will never know everything
about the world around them.
• Scientists modify their explanations as new
information becomes available.
What is a scientific investigation?
• Different types of scientific questions call for
different types of investigations (ways of
answering a scientific question).
• Field study is an investigation in which
scientists make observations and collect
information outside of the laboratory.
• Model is a representation of an object or an
event that is used as a tool for understanding
the natural world.
What is a scientific investigation?
(cont.)
• Controlled experiment is a scientific
experiment that involves changing one
factor and observing its effects on one
thing while keeping all other things
constant.
– This allows scientists to determine a
cause-and-effect relationship among the
factors (variables) that are changed in the
experiment.
What is a scientific investigation?
(cont.)
• Independent variable is the variable
that is changed (manipulated) in an
experiment.
• Dependent variable is the variable that
changes as a result of a change in the
independent variable.
• Scientists try to keep all other variables
constant or unchanged.
What is a scientific investigation?
(cont.)
• A controlled experiment must have two
groups:
– Control group – the independent variable
is not changed in this group.
– Experimental group – the independent
variable is changed in this group.
Both groups include the same factors
under the same conditions.
How do scientists communicate?
• It is important for scientists to
communicate to others the results of the
investigation as well as the methods by
which the investigation was done.
• This way the work can be repeated by
others to make sure the conclusions
were correct or to revise the investigation
or to perform related investigations.
How do scientists communicate?
(cont.)
• Scientists may publish reports in journals,
books, and on the Internet to show other
scientists the work that was done.
• Scientists may attend meetings where
they give presentations about their work.
Scientific explanations are accepted
only after they have been shown to be
reliable and lead to accurate
predictions about future investigations.
How do scientists communicate?
(cont.)
• After a scientific explanation has been accepted
by the scientific community, a scientific theory is
formed.
• Scientific theory is a possible explanation for
repeatedly observed patterns in nature supported
by observations and results from many
investigations.
– Ex. Einstein’s theory of relativity
– Theories in science are supported by observations
and results from many investigations.
How do scientists communicate?
(cont.)
• Scientific law is a rule that describes a
pattern in nature but does not try to
explain why something happens.
– Ex. Newton’s laws of Motion.
– For an observation to be a scientific law,
it must be observed repeatedly.
How is science applied?
• Although learning the answers to scientific
questions is important, the answers do not
help people unless that information can be
applied in some way.
• Technology
is the use of
science to
help people
in some
way.
Which describes an explanation
that is based on knowledge
gained from many observations
and investigation?
A. inference
B. prediction
C. scientific law
D. scientific theory
The variable that is changed in a
controlled experiment is called
the
A. independent variable
B. dependent variable
C. control variable
D. experimental variable
Which term refers to the practical
use of scientific knowledge,
especially for industrial or
commercial use?
A. technology
B. scientific law
C. inference
D. critical thinking
The Scientific Method
Essential Question
• What process do scientists use to
gather information?
The Scientific Method
Scientific
method
Hypothesis
Data
What do scientists do?
• The scientific method is used by all kinds
of scientists to investigate and answer
questions.
• Scientific method is a series of steps
that scientists use when performing an
experiment.
What do scientists do? (cont.)
• Scientists do not always
follow all the steps of the
scientific method in
order.
• However, they always
keep careful records of
what they have done and
observed.
• Hypothesis is an
explanation that can be
tested with a scientific
investigation.
How do scientists test their
hypothesis?
• Scientists need to collect data.
• Data (singular datum) are information
that is gathered during an investigation.
– Data can be recorded in the form of
descriptions, tables, charts, graphs or
drawings.
How do scientists analyze data?
• Scientists review all of the recorded
observations and measurements.
– They organize the data as a chart such as a table,
a graph, a diagram, a map, or a group of pictures.
– They look for patterns in the chart that show
connections between important variables in the
hypothesis being tested.
• Make sure to check the data by comparing
it to data from other sources.
How do scientists draw
conclusions?
• A conclusion is a statement about whether or
not the hypothesis is valid based on the data
collected.
– Decide if the data clearly support or do not support
the hypothesis.
– If the results are not clear, rethink how the
hypothesis was tested and make a new plan
– Record the results to share with others.
• Make sure to ask new questions
Which is a hypothesis?
A. The ball rolled 5 meters in 21
seconds.
B. If the ramp is steeper, then the ball
will roll faster.
C. The ball is red and made of rubber.
D. The speed of the ball is calculated by
dividing distance by time.
If the results from your
investigation do not support your
hypothesis, what should you do?
A. Modify your hypothesis.
B. Repeat the investigation until it
agrees with your hypothesis.
C. You should not do anything.
D. Change your data.
Tools of the Scientist
Essential Question
• How do scientists collect, analyze
and communicate data?
Tools of the Scientist
Quantitative
data
Precision
Qualitative
data
Mean
Description
Explanation
Consistency
Median
Range
What are types of data?
There are two general types of data:
• Quantitative data descriptions of the
natural world using numbers.
– Ex. Length, width, height, mass and
weight.
• Qualitative data are descriptions of the
natural world using words.
– Ex. Colors, smells, textures and tastes.
What are types of data? (cont.)
• One way to evaluate quantitative data is
to determine whether they are precise.
• Precision is how closely measurements
are to each other and how carefully
measurements are made.
– Are the following measurements
precise? 4.2cm, 4.1cm, 4.2cm
range is 4.2 - 4.1 = 0.1 (good precision)
What are types of data? (cont.)
– Precision is affected by the measuring
tool and the consistency of the person
making the measurement.
• Consistency is the ability to repeat a
task with little variation.
How do scientists collect data?
• Scientists use many different tools to
collect data.
• Rulers and metersticks are used to
measure length.
How do scientists collect data? (cont.)
• Glassware is used to measure volume
and hold liquids.
– Ex. Beakers, test tubes and graduated
cylinders.
– Volume is the amount space an object
takes up.
• Thermometers are used to measure
temperature.
How do scientists collect data? (cont.)
• Balances and Scales are used to
measure mass.
– Mass is the amount of material in an
object.
• Computers and the Internet are used
to collect, organize, analyze and display
data as well as to do research and
share scientific information on the
Internet.
How do scientists collect data? (cont.)
• To measure objects, Metric System base units
systems of standard
Quantity
Unit (symbol)
units have been
Measured
developed.
– A standard unit is a
measurement that
people agree to use.
• Scientists use
standard units in the
metric system.
Length
Meter (m)
Mass
Gram (g)
Volume
Liter (L)
Temperature
Degrees
Celsius (°C)
How to scientists collect data? (cont.)
• The metric system is
based on units of 10.
– Ex. 1 centimeter is
divided into 10
millimeters.
• Metric units can be
converted to smaller
or larger metric
system units by
multiplying or dividing
by 10.
Common Metric Unit
Prefixes
Prefix
Meaning
Kilo – (K)
1,000
Deka – (da)
10
Deci – (d)
0.1
Centi - (c)
0.01
Milli – (m)
0.001
Micro – (µ)
0.000001
How do scientists communicate
data?
• Everyone who deals with numbers, compares
measurements or collects data needs an
organized way to collect, analyze and display
the data.
• Graphs are used to organize and summarize
data as well as show relationships between
data in a visual way.
– Ex. Bar graphs, line graphs and circle graphs
How do scientists communicate
data? (cont.)
• Tables are used to display information in rows
and columns so it is easier to read and
understand.
• Statistics are often used to summarize and
evaluate data. The mean, median, mode, and
range are used to summarize a set of
quantitative data.
How do scientists communicate
data? (cont.)
– Mean is the sum of the numbers in a set of
data divided by the number of entries in the
set.
– Median is the middle number in a data set
when the data are arranged in numerical
order.
– Mode is the number that appears most often.
– Range is the difference between the highest
and lowest values in a data set.
How can we stay safe in the lab?
• In your science class, you will perform
many types of investigations. Before
performing these investigations, you
must learn how to keep yourself and
others safe by using safe practices.
– Think before you act.
– Follow your teacher’s instructions.
– Always wear correct protective clothing and
equipment for the investigation that you are
performing.
How can we stay safe in the lab? (cont.)
– Know the location of safety equipment.
– Always read the directions before you begin.
– Always wash hands before and after an
investigation.
– Use caution when working with animals and
treat them with care.
Which tool would be best to use
to measure the volume of a
liquid?
A. Meterstick
B. Thermometer
C. Test tube
D. Graduated cylinder
Which statistic is the middle
number in a data set
A. mean
B. range
C. median
D. mode
Visual Summary
Chapter Review
Standardized Test Practice
Scientists conduct scientific
investigations to answer
questions about the natural
world. They use various tools,
skills, and a process called the
scientific method to perform
scientific investigations.
Lesson 1: The Nature of Science
• Science is a way of learning about the
natural world.
• Scientists conduct experiments and
field studies and build models to
answer scientific questions.
• In a controlled experiment, the
independent variable is the factor a
scientist changes to observe how it
affects the dependent variable.
Lesson 2: The Scientific Method
• The scientific method is a process
scientists use to answer their
questions.
• A hypothesis is a possible explanation
for why something occurs. Scientists
gather and analyze data to test their
hypothesis and draw conclusions about
their investigation.
Lesson 3: Tools of the Scientist
• Scientists use tools to collect precise
data.
• Scientists communicate with one
another to share important information.
They use tables, graphs and statistics
to organize and communicate their
data.
• Mean, median and range are some of
the statistics used to summarize
quantitative data.
Which will not protect you from
acid that spills out of a beaker?
A. gloves
B. fire extinguisher
C. goggles
D. apron
What explains something that
takes place in the natural world?
A. technology
B. experiments
C. scientific theory
D. scientific law
Which increases the reliability of
a scientific explanation?
A. vague statements
B. repeatable data
C. several likely explanations
D. notes taken after an investigation
Which type of display would best
show the number of wins for each
football team in your school
district?
A. line graph
B. circle graph
C. metric units
D. bar graph
A family has five children. Which
statistic would identify the middle
child?
A. median
B. mean
C. range
D. mode
Mai Lin is conducting an experiment to see if
the height from which she drops a rubber
ball will affect the height to which the ball
bounces. Which is the independent variable
in her experiment?
A. the rubber ball
B. the height the ball bounces
C. the height from which the ball is
dropped
D. the mass of the ball
Which type of graph should be
used to show the composition of
gasses in Earth’s atmosphere?
A. line graph
B. circle graph
C. scatter plot
D. bar graph
Why would scientists want to
calculate the range of a set of
data?
A.
to identify the middle number in the data set
B.
to make sure the procedures were followed
correctly
C.
to understand the amount of variation in the
data set
D.
to identify the lowest number in the data set
Why might there be some
variation in data collected?
A. The measurement tool used may not
be precise.
B. A hypothesis was formed.
C. The scientist used quantitative data.
D. The data was organized in a table.
If you use a computer to make a
three-dimensional picture of a
building, it is an example of a
A. hypothesis
B. scientific law
C. model
D. controlled experiment