Brine Shrimp
Hatching Experiment
Brine Shrimp (Artemia franciscana) are small shrimp that live in extremely salty water such as The
Great Salt Lake in Utah. Brine Shrimp can be bought at any pet store, will hatch
within 24 hours, and become mature in about a week. Because of these qualities,
working with Brine Shrimp can help us learn how to design a good experiment.
You will design an experiment that will tell you something about
how environmental variables affect the hatching of Brine Shrimp. For example, is
the saltiness (salinity) of the water important? How much food is necessary?
The primary food source for brine shrimp is yeast.
If you design your experiment carefully you will be able to answer
one of these questions by counting the number of shrimp that hatched under
different conditions. Listed below are the independent variables that we will
be looking at as a class. Each of you will be focusing on one of these
variables (good experimental design only focuses on one independent variable at
a time).
Salinity (saltiness)
Yeast concentration
When we design an experiment we want to think about comparing a
Control group and a Treatment group. The control is what might be called the
normal conditions and the treatment is what we changed to test the variable we
want to study.
For example, if we want to test the effect of salinity on
hatching, we would compare how brine shrimp hatch under normal conditions, which
is in high salinity (very salty) water, to how they hatch low salinity (fresh)
water. Sea water is an average of 3.5% saline. In this case the control is high
salinity and the treatment is the solutions of decreasing salinity.
In this experiment we want everything else to be the same
between the control and the treatment groups except for the one variable that
we want to study. If you are studying the effect of the food supply, then
control your salinity. If you are studying the effect of salinity, then control
your food supply. Good luck. The best hatchers earn bonus points on this
assignment. We will write a complete lab report next week.
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| This is a picture of the supplies for your lab report. |
Format
for Lab Report
Introduction (25 points)
Consists of:
1. Purpose
statement: The hint is to look at the LO. A sentence stem looks something like,
“The purpose of this lab…”
2. Three
supporting details. Look at your resources or Freyer Model.
3. Ends
with a hypothesis. Make a specific, testable prediction about what will happen.
Quantitative not Qualitative.
Procedure (25 points)
Consists of:
1.A
materials list
2. Step
by step, numbered instructions for how to conduct this lab
Results (25 points)
Consists of:
1. Data
Table and Graph
2. Written
explanation of the data table and graph.
Conclusions (25 points)
Consists of:
1. A
statement about whether the data supports or contradicts your hypothesis.
2. Explanation
of why this occurred. What went right? Wrong?
3. What
you would do differently if this experiment where repeated.
