1.6 the scientific method name objectivesafter comple

1. 1.6 The Scientific Method
Name:
Objectives:
After completion of this activity students will be able to:1.
apply the scientific method in experiment design and analysis;2.
use appropriate academic resources to research and evaluate
environmental issues; 3. demonstrate how natural systems
operate and interrelate with one another; and4. evaluate and
graph experimental data for aquatic ecosystems.Introduction:
The Scientific Method
The scientific method is just a way to use critical thinking.
Many people do not check out the facts of the latest email story
and just pass it along to friends. For example, dihydrogen
monoxide (DHMO) is seen by some as the latest chemical threat
on college campuses. But what is it really?
(see http://www.dhmo.org/facts.html). Hint- do some lateral
research to find out what DHMO really is….
For more fun items like this, read this satirical article from The
Onion (http://www.theonion.com) that some people might not
realize these stories and articles are not true. For example,
review the article EPA: Stubborn Environment Refusing to Meet
Civilization Halfway (http://www.theonion.com/articles/epa-
stubborn-environment-refusing-to-meet-civiliza,17418/) and see
if you can find any information that might mislead you to the
meaning of the article. If you can figure out what DHMO really
is, then you don’t have anything to worry about in science
class. If you did not, then this is an opportunity to train
yourself to think a little more critically and become more
comfortable with science.

2. Much of science involves observation and recording those
observations and making sense out of them. Sometimes science
involves deliberate experimentation in which variables are
manipulated and the results help determine the relationship of
those variables. Whether you are making observations of the
world, or doing experiments, each involves collecting data,
analyzing the data, and developing conclusions that someone
else can replicate. If you design and build a kitchen table, you
would want to write the instructions in a way in which your
neighbor or friend could use your design and build the same
table. That is the way with the scientific method – you want to
make sure the observations you make, experiment you conduct,
and the analysis you do can be done by anyone else and that
they would get the same results.
Your hypothesis is an idea about the relationship of variables,
or even whether a news article is really factual, and you test it
with observations (research) or experimentation and then
determine whether the hypothesis is supported or not. While a
hypothesis is an idea, a theory is a well-founded explanation
based on testing using the scientific method. Most well-known
scientific theories have been tested many times and not shown
to be false. The term “theory” is also used in common language
to suggest an idea, but a scientific theory is based on testing,
such as the Cell Theory.
In this class, your hypothesis should specifically predict the
behavior of the dependent variable (what will be changing
depending on the other variable, the independent variable).
Take a look at the graph above of Bay Grass Abundance
(acreage) vs time (i.e., year) –
(http://stat.chesapeakebay.net/?q=node/129). The dependent

3. variable is always on the Y-axis (side) of a graph (e.g., Bay
Grass Abundance) and the independent variable on the bottom,
or X-axis (e.g., year). The Bay Grass acreage is changing
depending on the year.
You may find it easier to write your hypothesis in the form
of IF, THEN, such as IF I add drops of vinegar to water (the
number of drops added would be on the x-axis), THEN the pH
in the water will decrease (pH would be on the y-axis).
Using To learn more about independent and dependent
variables, check out
http://nces.ed.gov/nceskids/help/user_guide/graph/variables.asp.
Once you have made your hypothesis, the next step is to test it
by performing an experiment. Experiments must control for all
variable except the one you are looking at. So the conditions
must be identical except for the dependent variable, in this case
the acreage. Each experiment must also have a control group.
This means a group that the variable is unchanged. For
example, if you are doing an experiment looking at how
shortened sunlight affects leaf fall in oak trees, the
experimental group of trees would have shortened amounts of
daylight, but the control group would have trees with a constant
amount of daylight. By comparing the control group and the
experimental group, we can determine if the change was really
caused by the amount of sunlight or if another variable is at
play.
The fun just starting after the experiment is done. Now you
have to analyze your data. Data analysis involves grouping the
data into tables and graphs that show the relationship betw een
the two variables. Looking at the tables and graphs should give
you an answer as to whether to accept or reject your hypothesis,
which is the final step of the Scientific Method. If the data
matches your hypothesis, then you can accept it, but if the data
does not, you reject it and come up with another hypothesis and
start over again!

4. Analysis Questions:
Please respond to the following:
1) Conduct online research describing the relationship of
dissolved oxygen concentration and fish populations (number of
fish) using at least 3 reputable and/or scholarly sources. Write
1-2 paragraphs (at least 300 words) describing what you have
learned during your research. Use APA style formatting for
both the in-text citations and the end of text citations.
2) Based on your research, formulate a hypothesis on the
expected relationship between the number of fish found and the
dissolved oxygen concentrations. Remember to use an IF-
THEN format and only include the two variables of fish and
dissolved oxygen.
3) Create a scatter plot graph of the data set and include a
trendline. Identify the dependent (y-axis) and independent
variables (x-axis). You should not include the pond number,
but please do provide a title for the graph, and include a title for
each axis, and the units for each axis.
Pond Number
Dissolved Oxygen (mg/L)
Fish (#/seine)
1
0
0
2
2
0
3
3
6
4

5. 4
15
5
5
18
6
7
24
7
9
26
8
10
25
4) Based on the data in the table above, determine whether you
would accept, or reject, your hypothesis. Please make sure to
explain your reasoning.
5) Does the number of fish affect the dissolved oxygen, or does
the dissolved oxygen affect the number of fish? Please explain
your reasoning.
6) Please identify the relationship between DHMO, oxygen and
fish populations and explain your reasoning. Also, explain
whether you think DHMO is toxic to fish (why or why not).
Please also include the most common name for DHMO. Cite
your sources!
Revised 2019 1.6 - 4