Science: Brine Shrimp Experiment”
Question to be explored: Does alcohol damage a developing organism?
II. Hypothesis or prediction: Alcohol will decrease the number of brine
shrimp that will hatch from their eggs.
shrimp egg pack
1 Screw-capped jar containing premeasured marine salt
4 60 mm Petri dishes with lids
3 1 ml Pipets
1 5 ml Pipet
1 Magnifying glass (dissecting microscope, optional)
water (recommended) or *tap water that is dechlorinated
1 ml of 100% Ethanol
(alcohol; ethyl alcohol)***
***Important information regarding
ethanol (alcohol) to be used for this experiment.
1. Absolute (100% also
known as 200 proof), non-denatured grain alcohol is required. Do not use rubbing
alcohol, or ethanol that is denatured with a contaminant such as benzene.
2. If you elect to substitute an over-the-counter alcoholic beverage, be sure
to note the “proof” and adjust volumes accordingly. For example, should
you utilize a 100 proof alcoholic beverage such as some vodkas or bourbons, simply
double the volume of alcohol added to each dish. For the 1% condition use 0.2
mls; for the 2.5% use 0.5 mls and for the 5% condition use 1.0 mls.
In order to keep volumes reasonably small, we recommend that you use alcoholic
beverages that are greater than 80 proof. Particularly useful is 190 proof grain
alcohol (95% ethanol) which is readily obtainable and can be delivered at volumes
that are virtually the same as those for 100% ethanol (For the 1% condition use
0.1 mls; for the 2.5% condition use 0.25 mls and for the 5% condition use 0.5
4. Alcoholic beverages suitable for this experiment can be obtained
by adults from local alcoholic beverage suppliers or from on-line liquor stores.
Day 1— Preparation.
experiment requires dechlorinated water. The day before the start of the experiment,
fill a 500-1000 ml container with tap water and leave out overnight, uncovered.
This will dechlorinate the water. *The effectiveness of this dechlorination method
can be variable depending upon the chemical treatment of a given water supply.
Alternatively, bottled spring water, available in most grocery stores, can be
used successfully in this experiment. (Tip: To improve brine shrimp egg hatching,
aerate the water overnight beginning on Day 1 by using an airstone attached to
an aquarium pump.)
Day 2—Set up experiment.
1. Add 500 mls of
dechlorinated water to the screw-capped jar with the premeasured marine salt,
or mix with 12g (1 Tablespoon) of marine salt. Secure the cap and shake vigorously
to dissolve. Using a 5 ml pipet, transfer 10 mls of the marine salt solution into
each of the four 60 mm petri dishes.
2. Label the bottoms (lids can get mixed
up) of the petri dishes 1 through 4.
3. Petri dish #1 will have no ethanol
added to it. This will be the control condition.
4. To petri dish #2, add
0.1 ml of 100% ethanol (final ethanol concentration of 1%).
5. To petri dish
#3, add 0.25 ml of 100% ethanol (final ethanol concentration of 2.5%).
To petri dish #4 add 0.5 ml of 100% ethanol (final ethanol concentration of 5%).
7. Mark each of the toothpicks at an equal point (about 1/4 inch or 6 mm from
the end) so that each can be used to transfer relatively equivalent numbers of
eggs. Wet a toothpick in the marine salt solution and insert it up to the 1/4
inch mark into the packet of brine shrimp eggs. Release the adherent eggs by submerging
the toothpick in the pertri dish. Repeat for each of the four petri dishes using
a fresh toothpick for each petri dish.
8. Cover each petri dish with the correct
9. Allow the dishes to sit 48 hours, undisturbed. Dishes may sit up to
72 hours, if necessary. To increase the number of hatched brine shrimp, place
the petri dishes under an incandescent lamp for 48 hours, or double the number
of eggs added to each petri dish.
Day 3— Wait
Data collection and analysis
10. After forty-eight hours, examine each
petri dish with a magnifying glass or dissecting microscope and record your observations.
You may observe a) live brine shrimp, b) dead or immature brine shrimp and c)
unhatched eggs, as shown in the picture below. *(See #1 below for possible extended
IV. Results and Conclusions
11. Summarize your results by making a table that shows what you observed
for each condition, each day of the experiment or by filling out a data sheet
provided by your teacher.
12. Answer the questions on the worksheet.
Students submit the completed tables, their conclusions and completed worksheets
may quantify their results by sampling a small volume from each petri dish at
two different time points; at 0 hours to determine the density of eggs (eggs per
unit volume), and 48 hours later to quantify the ratio of live brine shrimp to
other (which includes unhatched eggs, partially hatched eggs and dead brine shrimp)
as a measure of viability. Students remove a 0.1 ml sample from each dish using
a 1 ml pipet, and place the droplet on a slide. A fresh pipet should be used for
each sample. Care should be taken to replace lids as soon as possible to avoid
evaporation of the alcohol. Using the magnifying glass or dissecting microscope,
the number of live brine shrimp, unhatched eggs, partially hatched and dead brine
shrimp can be determined and recorded in the data sheet entitled “Quantification
of Brine Shrimp Egg Hatching”. Graph the results.
2. For greater
impact and with local approval, you may consider replacing 100% (200 proof) ethanol
with a 100 proof alcoholic beverage such as some vodkas or bourbons. Simply double
the volume of alcohol added to each dish. For the 1% condition use 0.2 mls; for
the 2.5% use 0.5 mls and for the 5% condition use 1.0 mls.
can explore the influence of additional variables that may influence brine shrimp
egg hatching. Some suggested variables to consider are a) temperature and b) other
agents that may be dissolved in the salt water.