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Osmosis Egg Lab
Transcript of Osmosis Egg Lab
How can we observe osmosis across a semi-permeable membrane?
If we put the egg in corn syrup, then it will shrivel up because the corn syrup makes it hypertonic.
If we put the egg in water, then it will enlarge/swell because water makes it hypotonic.
One chicken egg
Solution One: 180 mL of corn syrup
Measuring cup or graduated cylinder
One glass jar/cup
Solution Two: 200 mL of tap water
Two feet of string/yarn
Extra water(to wash out beaker)
Paper towels (to clean up afterward)
1. Mr. Gatlin soaked chicken eggs in vinegar over the weekend to dissolve the shell.
2. Measure circumference of the egg with one person holding the egg while another person takes a piece of yarn and wraps it around the egg.
3. Cut the yarn where it starts to overlap and measure it using a ruler.
4. Place the egg back in the beaker.
5. Place the beaker on the measuring scale with the egg in it and record mass in grams.
6. Have one person hold down the egg in the beaker while another person fills the beaker with corn syrup until the egg is fully submerged.
7. Let the egg soak for 24 hours.
8. Measure the circumference and mass the same way as the previous day.
9. Pour 200 mL of water into beaker.
10. Place the egg back into the beaker.
11. Let the egg soak in the water for 24 hours.
12. Pour the water out of the beaker.
13. Measure egg mass and circumference the same way as the previous times.
14. Pop egg with a paperclip and dispose of egg.
15. Clean out the beaker with soap and water.
Speck like shell remnants
Smells like rotten eggs and vinegar
Mass -82. 4 grams
Circumference - 16.5 cm
Mass = 51.2 g
Circumference = 13.5 cm
Percent of change for mass = -38%
Pecent of change for circumference = -18%
Looks like deflated balloon
Mass = 79.1 grams
Circumference = 15 cm
Percent of change for mass = 54%
Percent of change for circumference = 11%
Yolk is visible
Massengale, C. "Effects of Solutions on Cells." Biology Class Notes. N.p., n.d. Web. 3 Oct. 2013. <http://www.biologyjunction.com/effect_of_solutions_on_cells.htm>.
Gatlin, Johnny. "Osmosis." Panther Creek High School. Sept. 2013. Lecture.
"MCAT Daily." : Difference between Hypertonic, Hypotonic, and Isotonic? N.p., 14 May 2010. Web. 03 Oct. 2013. <http://mcatdaily.blogspot.com/2010/05/difference-between-hypertonic-hypotonic.html>.
For this lab our group had two hypotheses. One was "If we put the egg in corn syrup, then it will shrivel up because the corn syrup makes it hypertonic." The other was "If we put the egg in water, it will enlarge/swell because water makes it hypotonic." Both of these hypotheses were correct, as shown by the data. The egg began at a mass of 82.4 grams. When placed in the hypertonic solution, it shrunk to 51.2 grams, a -38% decrease. When placed in the hypotonic solution, it increased 54% to become 79.1 grams. In addition, the circumference data also supports our hypotheses. The egg started off with a circumference of 16.5 cm. It was then placed in the hypertonic solution to shrink -18% and become 13.5 cm. Then, it was placed in a hypotonic solution to grow 11% and become 15 cm. These measurements show that the egg shriveled during its period in the hypertonic solution and grew during its time in the hypotonic, therefore proving our hypotheses correct.
Osmosis is a process by which water molecules tend to pass through a semi-permeable membrane from an area of higher concentration to an area of lower concentration, until equilibrium occurs. Hypertonic solutions have a higher concentration gradient inside of a cell, while hypotonic solutions have a higher concentration gradient outside of the cell. When a plant cell is immersed in a hypertonic solution, water leaves the cell and the cytoplasm shrinks and plasmolyses. When an animal cell is placed in a hypertonic solution, water leaves the cell and the cell shrinks, causing it to crenate. This occurs because the molecules want to reach equilibrium, so water moves out since there is more water inside the cell than there is outside. When a plant cell is immersed in a hypotonic solution, water enters the cell and the cell swells a bit and becomes turgid. When an animal cell is placed in a hypotonic solution, water enters the cell and the cell swells and may burst. This occurs because the molecules want to reach equilibrium, so water moves in since there is less water inside the cell than there is outside.
Different types of solutions and their effects on cells
1. The dependent variables were the mass and circumference of the egg.
The independent variables were the type of solution you put the egg in.
2. Day 1 was the control when you took the egg out of the vinegar. You need a control to be able to compare and contrast how the egg size might have changed.
3. The egg swelled up in the water because the interior of the egg had lower concentration gradient than the surrounding water, so water entered the egg making it swell.
4. The egg shrunk in the corn syrup because the interior of the egg had a lower solute concentration than the surrounding corn syrup, so the water was "pulled out" of the egg causing it to shrink.
5. The results supported the hypothesis. We predicted that the egg would shrivel in corn syrup because the corn syrup is hypertonic. We also predicted that the water would make the egg swell because the water is hypotonic which was also correct.
6. Osmosis is the diffusion of water molecules across a semi permeable membrane from an area of higher concentration to an area of lower concentration. It is a method of passive transport. Water is being moved. Substances will either move into or out of the cell.
7. Passive transport goes from an area of higher concentration to an area of lower concentration. Active goes from an area of lower concentration to higher. Active requires energy. Active energy is also found in the form of endocytosis and exocytosis, but passive is found through osmosis, diffusion, and facilitated diffusion.
8. There were not really any errors. We could have been more precise with the measuring, but it did not affect the overall outcome of the experiment.
Independent variable: type of solution
Dependent variable: size of the egg
Constants: egg, string, ruler, and beaker
Control: the egg at day one
Egg in vineger. Photograph. n.d.. Imagination Station. http://imaginationstationtoledo.org/content/wp-content/uploads/2011/04/egg-in-vinegar.jpg. 06 Oct. 2013.
Hypertonic Egg. Photograph. n.d.. McCarter Biology. http://mccarterbiology.edublogs.org/labs/diffusion-and-cell-membranes/. 06 Oct. 2013
Hypotonic Egg. Drawing. n.d.. Biology Junction. http://www.biologyjunction.com/egg_osmosis_sample1_lab.htm. 06 Oct 2013