An Egg-cellent Experiment

An Egg-cellent Experiment!
In the 2nd quarter performance assessment, you will investigate how a cell membrane works to let water
enter and leave the cell. You will use a chicken egg as a model of a cell. After dissolving the shell in
vinegar to expose the membrane, you will soak the egg in varying liquids and keep a daily record of
observations as well measurements of the circumference for egg.
Investigative Question:
How will an egg change as it is exposed to vinegar, freshwater, saltwater, colored water, and syrup?
Things to consider:
Identify the Independent Variable in the Egg Experiment. Explain how you know this is the I.V.
Identify the Dependent Variable in the Egg Experiment. Explain how you know this is the D.V.
Identify three Controlled Variables in this lab. Explain why controlled variables are important in this lab.
Write a hypothesis about how your egg will change in each of the four liquids. This hypothesis will be at
least 4 sentences.
Materials: one chicken egg, vinegar, 10% salt water solution, food coloring, water, syrup, cup or beaker,
flexible measuring tape
1. Determine the circumference of an unboiled egg. To measure the circumferences of the egg use a
flexible measuring tape. If you do not have a measuring tape rap string snugly around at the
equator of the egg, grasp the string between your thumb and finger exactly at the point where the
end of the string meets the rest of the string. After circling the egg, keep your thumb and finger in
place then lay the string straight on a flat surface. Use a metric ruler to measure the distance from
each end and record your measurement in millimeters on your data table.
2. Fill a cup or beaker with enough vinegar to completely cover the egg. Soak your egg in vinegar for
2 to 3 days.
3. Carefully take the egg out of the liquid and pour the liquid down the drain.
4. Rinse off the egg in cold water over the sink and blot it dry with a paper towel.
5. Remove the shell from the egg.
6. Observe and record how it has changed after putting the egg in vinegar.
7. Measure and record the circumference of the egg.
8. Rinse the cup clean and replace the vinegar with enough freshwater to cover the egg.
9. Return your egg to the cup with the freshwater for two days.
10. After 2 days in freshwater remove the egg. Observe and measure the egg’s circumference in
11. Carefully remove the egg from the freshwater and pour the liquid down the drain.
12. Replace the freshwater with the same amount of saltwater
13. After 2 days in freshwater repeat the observation and measure then replace freshwater with
14. Remove the egg from the saltwater after 2 days and pour the liquid down the drain.
15. Make several observations and measure the circumference in millimeters
16. Replace the saltwater with colored water for at least two days.
17. Remove the egg from the colored water and pour the liquid down the drain.
18. Replace the colored water with syrup. Let the egg sit in the syrup for one day.
19. After a day has passed, take the egg out of the syrup to be measured and observed.
20. Through out the cup and syrup in the trash can.
When the experiment is completed and all the data has been collected, write a lab report typed or
written neatly in ink, based on the data collected. The report must include each of these sections: (a)
investigative question (b) hypothesis (c) materials list (d) step by step procedure list (e) line graph about
measurements and observations, and (f) conclusion.
Tips for writing a good conclusion:
 Write a paragraph using complete sentences to sum up what you have learned from an
 You start the paragraph by telling your reader what you wanted to find out,
 your hypothesis,
 how you tested your hypothesis,
 Whether the data you collected supports your hypothesis or not.
 Point out the evidence that either supports or rejects your hypothesis.
 If your result is inconclusive, discuss possible errors in your data collection or plan new
experiments to address the issues.
 Finally, add information on how you can apply what you have learned from your experiment to a
real life situation or to make a prediction about a similar situation
Colored Water
Circumference (mm)
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