Unit 1
Scientific Inquiry
Essential Question #1
What role does
science play in the
study of life?
Textbook References : Unit 1
Miller & Levine: Ch. 1-The Science of Biology
1.1 What is Science (Pgs. 4-9)
1.2 Science in Context (Pgs. 10-16)
Campbell: Ch. 1- Biology: Exploring Life
1.7 & 1.8 The Process of Science (Pgs. 9-10)
1.9 Biology and Everyday Life (Pg. 12)
Unit Vocabulary
1. Biology
2. Quantitative Data
3. Observation
4. Conclusion
5. Ethics
6. Hypothesis
7. Inference
8. Generalization
9. Controlled Experiment
10. Independent Variable
11. Stimulus
12. Dependent Variable
13. Theory
14. Control Group
15. Experimental Group
16. Qualitative Data
17. Metric System
18. Line Graph
19. Bar Graph
20. Scientific Methodology
21. Discovery Science
22. Hypothesis-Based Science
23. Inquiry
What is Science?
• The word is derived from a
Latin verb meaning “to know”.
• It’s an organized way of
gathering and analyzing
evidence
• Science deals only with the
natural world.
• Scientists look for patterns and
connections among events.
What are the Goals
of Science?
• Scientists aim for the best understanding of
the natural world.
– To provide explanations for natural events.
– To use those explanations to understand patterns
& make useful predictions.
The Process of Science
• Biology blends two main types of scientific
exploration:
– Discovery science
– Hypothesis-based science
• Science as Inquiry:
– All science explorations begin with a question
– Science = “to know” in Latin
– In order “to know” you must ask a question (inquire)
• The questions are based on observations.
– the use of senses to gather and record information
about structures or processes.
• Recorded observations are called data
The Two Types of Data:
• Quantitative (think quantity)
measurements
– ex: height charts
• Qualitative (think quality)
descriptions
– ex: Jane Goodall and chimps
Discovery Science
• It is descriptive science.
• It describes natural
structures or processes
through observation and
data collection
• Alexander Fleming and the
discovery of penicillin
Steps of Discovery Science
•
•
•
•
•
Ask a question
Make observations
Collect data and analyze
Form a conclusion
A logical conclusion based on observations is
called an inference.
Example of an Inference
• Observation- the door bell rings
• Inference- somebody is waiting at the door
• Could the bell ringing infer something else?
• Generalizationa general conclusion based on many observations
Hypothesis-Based Science
Used to explain the natural world.
• How does it differ from Discovery science?
– You can describe and measure the growth of a
plant toward light (discovery), but what causes
this phenomenon? How can scientists explain the
plant’s ability to detect and respond to the
direction of the light (hypothesis-based)?
Scientific Methodology
A universal approach to studying science by using deductive reasoning.

Observations are made which lead to questions and inferences.

Hypotheses are formed based on our observations using
deductive reasoning.
The hypothesis must be testable
The hypothesis must be falsifiable

Experimentation is a way of gathering information/data as a
means of testing our hypotheses.
 Quantitative data: numerical information
 Qualitative data: information in the form of words

Results and Conclusions use experimental data as evidence to
support, refute, or revise the hypothesis being tested.
The Scientific Method
• Steps used to gather info. & answer questions.
QUESTION
RESEARCH
FORM HYPOTHESIS
EXPERIMENT
ANALYZE RESULTS
DRAW CONCLUSIONS
QUESTION
Observe and ask questions
What is it that you would like to know?
RESEARCH
Gather information
FORM HYPOTHESIS
Hypothesis(an educated guess)
-a possible explanation for your
question
-based on the info that you
gathered
-can be tested
EXPERIMENT
ExperimentAn investigation that tests your
hypothesis
VariableFactors that can change in an
experiment
Constantsthe variables that you control
Independent Variable
- the condition that is tested
(the one variable that you alter)
-it is the only factor that affects the
outcome
Dependent Variable
-the condition that you observe or measure
-results from changes made to the
independent variable
Control- A standard used to compare your results
(the absence of the independent
variable)
ANALYZE RESULTS
DRAW CONCLUSIONS
charts
tables
graphs
measurements
observations
Based on your results
what is the answer to your
original question?
Can you accept your
hypothesis?
If not, you must reject it
and start over!
Forming and Testing
a Hypothesis
• Tigger went camping one night and made the following
observation: “My flashlight doesn’t work!”
– The question is obvious.
• Why doesn’t my flashlight work?
• A reasonable hypothesis could be that the batteries are
dead.
Prediction
• If the batteries are dead
and he replaces them with
new ones, then the
flashlight will work.
• If the results of the test do
not support the hypothesis,
other hypotheses can be
formed and tested.
Examine the picture to the right
and assess your understanding of
how biologists use scientific
methodology to answer questions
about the natural world.
Observations:_______________________________
___________________________________________
___________________________________________
Hypothesis:_________________________________
___________________________________________
___________________________________________
› An observation is the act of noticing and
describing events or processes in a careful,
orderly way.
› For example, researchers observed that marsh
grass grows taller in some places than others.
› This observation led to a question:
 Why do marsh grasses grow to different heights in
different places?
› After posing questions, scientists use further
observations to make inferences, or logical
interpretations based on what is already known.
› Inference can lead to a hypothesis, or a scientific
explanation for a set of observations that can be tested
in ways that support or reject it.
› For example, researchers inferred that something
limits grass growth in some places.
› Based on their knowledge of salt marshes, they
hypothesized that marsh grass growth is limited by
available nitrogen.
1.
2.
3.
4.
Can you determine the following?
Control Group: __________________________________
Experimental Group: _____________________________
Independent Variable: ____________________________
Dependent Variable: _____________________________
Use the picture above to explain the experiment:
_______________________________________________
_______________________________________________
_______________________________________________
› Testing a scientific hypothesis often involves designing
an experiment that keeps track of various factors that
can change, or variables.
 Examples of variables include temperature, light, time,
and availability of nutrients.
› Whenever possible, a hypothesis should be tested by
an experiment in which only one variable is changed.
› All other variables should be kept unchanged, or
controlled. This type of experiment is called a
controlled experiment.
› It is important to control variables because if several
variables are changed in the experiment, researchers
can’t easily tell which variable is responsible for any
results they observe.
› The variable that is deliberately changed is called
the independent variable.
 also called the manipulated variable.
› The variable that is observed and that changes in
response to the independent variable is called the
dependent variable
 also called the responding variable.
› Typically, an experiment is divided into control
and experimental groups.
› A control group is exposed to the same
conditions as the experimental group except for
one independent variable.
› Scientists set up several sets of control and
experimental groups to try to reproduce or
replicate their observations.
› For example, the researchers selected similar plots of
marsh grass. All plots had similar plant density, soil
type, input of freshwater, and height above average
tide level. The plots were divided into control and
experimental groups.
› The researchers added nitrogen fertilizer (the
independent variable) to the experimental plots.
› They then observed the growth of marsh grass (the
dependent variable) in both experimental and control
plots.
Results:
________________________________________________
________________________________________________
Analysis :
________________________________________________
________________________________________________
Conclusion: Remember that your conclusion is the
answer to your hypothesis.
________________________________________________
________________________________________________
› Scientists choose appropriate tools for collecting
and analyzing data.
› Tools include simple devices such as
metersticks, sophisticated equipment such as
machines that measure nitrogen content, and
charts and graphs that help scientists organize
their data.
• Scientists record experimental observations, gathering
information called data.
• Quantitative data are numbers obtained by counting or
measuring.
•
In the marsh grass experiment, it could include the number
of plants per plot, plant sizes, and growth rates.
• Qualitative data are descriptive and involve
characteristics that cannot usually be counted.
• In the marsh grass experiment, it might include notes about
foreign objects in the plots, or whether the grass was growing
upright or sideways.
In the past, data were recorded by hand.
 Today, researchers typically enter data into
computers, which make organizing and analyzing
data easier.

› This graph shows how grass height changed over time.
› The grass in the experimental group grew taller than
the grass in the control group.

Scientists use experimental data as evidence to support, refute,
or revise the hypothesis being tested, and to draw a valid
conclusion.
› Analysis- The marsh grass in the experimental group grew taller than
the grass in the control group because grass growth is limited by the
availability of nitrogen.
› Conclusion- The hypothesis is accepted based on these results.

New data may indicate that the researchers have the right
general idea but are wrong about a few particulars. In that case,
the original hypothesis is reevaluated and revised; new
predictions are made, and new experiments are designed.

Hypotheses may have to be revised and experiments redone
several times before a final hypothesis is supported and
conclusions can be drawn.

Can you propose one possible source of error in the
marsh grass experiment? Could there be another
reason for the grass to grow taller in the experimental
group?
_________________________________
_________________________________
_________________________________
› Researchers must be careful to avoid errors in
data collection and analysis. Tools used to
measure the size and weight of marsh grasses,
for example, have limited accuracy.
› Data analysis and sample size must be chosen
carefully. The larger the sample size, the more
reliably researchers can analyze variation and
evaluate differences between experimental and
control groups.





they are based on opinions
they are not based on your
actual results
your sample size is too small
you over-generalize based
on only a few tests
you do not have a control

Theory
› an explanation of a natural phenomenon
› based on scientific evidence from many investigations
› results from continued support of a hypothesis.
A picture is
worth a
thousand words!
copied from:
http://www.explorebiology.com/pptLE/

Variables
› what you measure in an experiment
› dependent variable
 measured variable
 unpredictable change: we don’t know how it will
change until we do the experiment
 Y-axis
The effect of
› independent variable
INDEPENDENT
_____________
on
 manipulated variable
DEPENDENT
_____________
 predictable change: it only
changes because we chose
how it would change
 X-axis
2005-2006

How does fertilizer affect the growth rate of
plants?
› we set up an experiment testing different amounts
of fertilizer on different plants & measuring the
growth (height) of the plants:
 dependent variable (Y-axis)?
 height of plants
 independent variable (X-axis)?
 amount of fertilizer
2005-2006
The effect of
Amount
of Fertilizer
_____________
on
Height
of Plants
_____________

How does exercise affect heart rate of 10th
grade student?
› we set up an experiment testing different lengths
of time of exercise (minutes) on the heart rate of
students:
 dependent variable (Y-axis)?
 heart rate
 independent variable (X-axis)?
 minutes of exercise
2005-2006
The effect of
Exercise
_____________
on
Heart Rate
_____________

What’s the favorite drink of students?
› we set up an experiment surveying students and
asking which is their favorite drink :
 dependent variable (Y-axis)?
 number of students
 independent variable (X-axis)?
 type of drink
The effect of
Type of Drink
_____________
on
How_____________
many students chose it
2005-2006

Graphs
How’s a critter
to choose?
› line graphs
 graphing data that shows continuous change
› bar graphs (or histograms)
 graphing data that is in disconnected groups
2005-2006
How does elevation affect temperature?
elevation
(feet above
sea level)
temp.
(°C)
0
30
500
25
20
18
1000
20
1500
15
15
2000
10
2500
5
Line graph!
30
temperature
25
10
1200 ft?
5
0
0
500
10001200
1500
2005-2006
elevation
2000
2500
Which drink do you like best?
number of students
6
Bar graph!
5
drink
number
Coke
1
Pepsi
1
Water
4
Iced tea
4
Gatorade
3
4
3
2
Favorite?
1
0
Coke
Pepsi
water
2005-2006
type
of drink
tea
Gatorade
Essential Question #1
What role does
science play in the
study of life?
By applying scientific
methodology, biologists
can find answers to
questions that arise in
the study of life.