BIOLOGY NOTES
SCIENTIFIC METHODS
PART 2
PAGES 13-18
Standards:
_____
1.2 Describe how scientific inferences are
drawn from scientific observations and provide
examples from the content being studied
1.3 Define a problem based on a specific body
____
of knowledge and: pose a question about the
natural world; plan an investigation; conduct
systematic observations; infer the meaning of
data collected to answer the question;
communicate the data and explanations to
others
____
1.6 Recognize that theories do not become
laws, nor do laws become theories; theories are
well supported explanations and laws are well
supported descriptions
Essential Questions:
1. What inferences can we make about living
things from our observations?
2. How can we tell science from
non-science?
I. The Goal of Science
investigate and
The goal of science is to ___________
understand nature
___________
• How is this goal accomplished? By using the
scientific ________
method
_________
Scientific Method = the use of certain
answers to questions
processes to find ________
about the world
• it is an _________
on-going process
• it provides us with a way of knowing ____
how and
why things occur in nature
_____
• it does NOT answer questions about
aesthetics (beauty) ______,
__________________,
ethics or morals
consistent
• It is considered science only if it is __________,
observable
natural ____________,
predictable
_____________,
________,
________
testable and _________
tentative
e.g. There are no scientific methods to discover if:
Is abortion right or wrong?
Is the Mona Lisa beautiful?
II. Steps of the Scientific Method
nature
1. Asking questions about ______
• Usually, a scientists seeks answers to topics
interesting to him or her
that are __________
e.g.Which bat is the best?
What are the healthiest foods for an
athlete?
“Lorenzo’s Oil”
2. Make observations about the _____
topic through
research or ___________
experience
_________
• Observations = information that is gathered
senses
using the five ________
 2 Types of observations:
a. quantitative observations = observations in
numerical form
___________
e.g. counting, temperature, mass,
density, volume, pH, area, etc.
b. qualitative observations = observations that are
____________
descriptive and do not involve __________
numbers
e.g. behavior, appearance, voice
recordings, tape recordings, etc.
3. Form a scientific ________
question
• A scientific question differs from a general
question because it is very ________
specific
_________
research allow a
 observations and _________
scientist to narrow his _______
search so that the
outcome answers a very precise question
e.g. A good scientific question would be:
What is the effect of lysol on
radish seeds?
A bad scientific question would be:
What is the effect of household
cleaners on plants?
4. Form a __________
hypothesis
• observations and research on a specific
scientific question lead scientists to make
inferences
__________
 inference = a logical explanation using
_____
prior knowledge, research or ___________
experience
e.g. You are interested in the subject of Daphnia,
or water fleas, and their heart rates. You know
caffeine speeds up human heart rates through
experience and research. You have already
formed the following scientific question: What
is the effect of caffeine on the heart rates of
Daphnia? What is a reasonable inference
based on your observations and research of
your topic?
caffeine speeds up
Daphnia heart rates
 hypothesis = a tentative, ________
testable
explanation for a question or problem.
What is the difference between a hypothesis
and an inference?
an inference is not testable
________________________
a hypothesis is not just a random ______
guess
to make a hypothesis testable apply ___
if and
_____
then statements
e.g. How could you turn your inference
above into a hypothesis?
If caffeine is given to Daphnia, then their
heart rate will increase .
5. Design an experiment
• Experiment = a __________
procedure that tests a
hypothesis by the process of collecting
___________
controlled conditions.
information under __________
time equipment used,
 light, temperature, _____,
type of material and use of _________
materials are all
different conditions or variables that could be
considered in any ___________
experiment
the goal of an experiment is to know that only
1 variable effects the _________
outcome
__
 controlled experiments test a hypothesis by
1 condition or ________
variable at a
changing only __
time
2 types of variables in controlled experiments:
a. independent variable = the variable that is
________
changed in the experiment; also known as
manipulated variable
the ___________
b. dependent variable = the variable that is
being _________
measured in the experiment; also
responding variable
known as the __________
e.g. It is hypothesized that if roses are given more
water than normal, then they will grow taller
than normal. To test this, a student grew 3
identical types of roses. One with a normal
amount of water, one with twice as much water
and one with three times the recommended
amount of water. They were given the same
amount of sunlight, plant food and type of
water.
1. What is the independent variable?
amount of water
2. What is the dependent variable?
rose growth
3. Why were all other variables kept the same?
to know that only water effects
the outcome
 in any experiment in which a scientists
changes how something naturally occurs, he or
she must also have a control ______
group to serve
comparison
as a basis of ___________
 control groups allow a scientists to compare
their outcome to what is ________
normally seen
e.g. In the example above, was there a control
group? If so, why?
yes because without a control group it
would not be known if any of the roses
grew more than normal
6. Collect Results
data can be
• Results, often called the _____,
collected in a variety of ways
e.g. notes, recordings, pictures, timing
measurements
laboratory
• Some results will be collected in a __________
under controlled conditions. Other results
cannot be collected in a lab. These types of
field _______.
studies
experiments are called _____
e.g. migratory paths of birds
• A good scientist will have results that include
quantitative and __________
qualitative
both ____________
observations
• Results from an experiment that are
quantitative can be represented easily using
___________
a ______
graph
 the independent variable would be on the
__________
horizontal axis (also called the ___
X axis)
while the dependent variable would be placed
on the _______
vertical axis (also called the ___
Y
axis).
e.g. Using the chart below to graph the results:
ROSE PLANT
1
2
3
AMOUNT WATER
40 mL
80 mL
120 mL
AMOUNT GROWTH
2 cm
10 cm
8 cm
7. Draw a conclusion
• Conclusion = a logical ___________
explanation that
summarizes the results or evidences and either
supports or denies the hypothesis.
_________
e.g. What was the conclusion of the rose
experiment?
more water = more growth
• A good scientist will repeat their experiments
many times so that their experiment can be
valid
considered _____
e.g. new medicines
valid
• Data and conclusions that are proven ______
because of repeated trials are often published
journals so that other scientists
in scientific ________
can test them.
III. Theories vs. Laws
If a particular hypothesis is supported by a large
body of evidence, over time, from many
investigations conducted by multiple
different _____________
theory
scientists then it can become a ______
• Theory = an explanation of natural
supported by a large
phenomenon that is __________
body of scientific evidence from many different
investigations and ____________;
observations
_____________
why things occur in nature
explanation of _____
e.g. theory of evolution, big bang theory
cell theory
 theories DO NOT become scientific _____
laws
thus, a theory is generally considered a
explanation for some sort of natural
universal ___________
phenomena
principles of nature;
• Scientific law = certain __________
how things occur in nature
descriptions of _____
e.g. gravity, inertia,
laws of thermodynamics
• What is the difference between a theory and a
law? theories describe why nature occurs
laws describe how nature occurs