Introduction
We did the experiment at school during the science class. This experiment was related to the osmosis. We were learning about the osmosis and the transportation. Osmosis is the net movement of water across a selectively permeable membrane driven by a difference in solute concentrations on the two sides of the membrane. Our purpose by doing this experiment was observing the egg in two different solutions, and find out how did the solutions affected to the egg. And not only observing it, but also compare the result with our prediction that we did before the experiment.
Materials needed
- 2 fresh eggs in their shells
- 2 plastic cups
- 100ml graduated cylinder
- Balance
- Water
- Ruler and string
- Vinegar
- Possible solutions : corn syrup, alcohol, distilled water, salty water(10% and 20%), tap water
Things that we need to prepare for the experiment
Before the experiment, we should prepare the shell removed egg. Ms. Silva prepared it for us, and the egg was in the water for 2 days. (9/13-9/14) While waiting for the shell removing, we predicted about the result of the experience. Our group selected alcohol, and salty water(20%). I said that the both of the egg will be bigger, because I thought that the concentration inside the egg would be lower than the outside (solution).
What did we do for three days?
First day (9/15/2011)
After removing the egg shell completely, we rinsed the egg with water carefully, and started the lab. We dried the egg with paper towel after washing it. We recorded the appearance, mass, and circumference of the eggs in the data table. After measuring all the datas, we put them in to the plastic cup with same amount of solution. Both eggs looked yellowish. The alcohol egg was bigger than the salty water egg. The circumference difference was more than 2cm, and the mass was also 15g bigger than the salty water egg. However, while other groups were putting 80ml of solution, our groups egg was too big so we've put 75ml each in the cup to do the experiment. We left the eggs for one days and checked it tomorrow.
(Our group didn't covered the top of the cups, so that solutions have might vaporized)
Second day (16/9/2011)
We did the same thing that we did on first day, pick up the egg from the solution, check the mass, circumference, and the amount of solution left in the plastic cup. The result from second day was kind of different with my prediction. I thought the both eggs would be bigger. However, the egg which was in the alcohol became smaller and the both eggs' size became same. But the amount of the solution left seems not right. Because if the water in the egg white from the alcohol egg came out to the alcohol, the amount of solution left should be more than 75ml. So I guessed that the amount of the alcohol decreased (little bit) because the alcohol vaporized. The amount of solution left in salty water(20%)'s cup was less than the alcohol. It decreased a lot because the water moved into the egg. When we observed the eggs' appearance, the alcohol egg became smaller, and the color of the egg changed into white. But, the salty water egg was still yellowish, but with more darker yellow, and the egg became bigger.
Third day (9/19/2011)
Of course, we did the same thing at the beginning of the third day, checking the mass, circumference, and the amount of solution left. (: It didn't take that long because we became professional (??haha..) during two previous days. I expected bigger differences, because the time passed a lot. But the amount of solution left of the alcohol didn't decreased a lot. I think there were no more water to come out from the egg, and some that decreased was vaporized. The change in salty water was not really different with the alcohol. It didn't decreased much, and I think it's the same reason with the alcohol egg's, because the concentration of inside egg, and the solution became same, so there were keeping the same concentration. ( it didn't stopped the osmosis! never!) Also, the alcohol egg became even smaller than the second day and whiter. And the salty water egg became bigger, and limpid, so that we could see through the egg.
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Here are my data table and the graphs. This will help you guys to see the changes between the two eggs. THE RED LINE IS SALTY WATER EGG, AND THE BLUE LINE IS ALCOHOL EGG.
*All the datas are calculated to the average rate.*
We did the same thing that we did on first day, pick up the egg from the solution, check the mass, circumference, and the amount of solution left in the plastic cup. The result from second day was kind of different with my prediction. I thought the both eggs would be bigger. However, the egg which was in the alcohol became smaller and the both eggs' size became same. But the amount of the solution left seems not right. Because if the water in the egg white from the alcohol egg came out to the alcohol, the amount of solution left should be more than 75ml. So I guessed that the amount of the alcohol decreased (little bit) because the alcohol vaporized. The amount of solution left in salty water(20%)'s cup was less than the alcohol. It decreased a lot because the water moved into the egg. When we observed the eggs' appearance, the alcohol egg became smaller, and the color of the egg changed into white. But, the salty water egg was still yellowish, but with more darker yellow, and the egg became bigger.
Third day (9/19/2011)
Of course, we did the same thing at the beginning of the third day, checking the mass, circumference, and the amount of solution left. (: It didn't take that long because we became professional (??haha..) during two previous days. I expected bigger differences, because the time passed a lot. But the amount of solution left of the alcohol didn't decreased a lot. I think there were no more water to come out from the egg, and some that decreased was vaporized. The change in salty water was not really different with the alcohol. It didn't decreased much, and I think it's the same reason with the alcohol egg's, because the concentration of inside egg, and the solution became same, so there were keeping the same concentration. ( it didn't stopped the osmosis! never!) Also, the alcohol egg became even smaller than the second day and whiter. And the salty water egg became bigger, and limpid, so that we could see through the egg.
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Here are my data table and the graphs. This will help you guys to see the changes between the two eggs. THE RED LINE IS SALTY WATER EGG, AND THE BLUE LINE IS ALCOHOL EGG.
*All the datas are calculated to the average rate.*
PICTURES :D
This is the picture of the eggs after we finished the lab. We cut them and see what happened inside the egg.
the salty water egg has more water inside, and the alcohol egg just looked like a boiled egg. The egg changed into solid. (WOW!)
Conclusion
First, the result of the experience was very interesting. Different with my prediction, the egg with the alcohol became smaller, and the egg with salty water became bigger. Based on the data that we collected, we can easily notice that alcohol egg decreased with everything, mass; from 74.2g to 64.1g, circumference; from 16.5cm to 14.8cm, and amount of solution left; from 77.5 to 50.5. We can guess that the water inside the egg came out from the egg and moved to the water outside. So it should be increased the amount of solution. However, since alcohol vaporize easily, we can say that the alcohol disappeared.
While the alcohol egg was getting smaller, the salty water (20%) egg's mass and circumference became bigger, which was same as my prediction, mass; from 66.7g to 77.3g, and circumference; from 15.3cm to 16.8cm. However, the amount of solution decreased, from 77.5ml to 57ml. Different with the alcohol egg, this time the water from the outside of the egg moved into the egg, because of the osmosis. And the point, that I learned from it is that it didn't stop transporting, but keeping the same concentration by giving and taking the same amount of water.
Examples - Osmosis/Diffusion affect living things?
I said that the osmosis and the diffusion totally affect to living things, because living things are made of cells, and in the cell, if there are too much water concentration around the cell, the cell swells up to have the same concentration as the outside by taking in water. Same as the previous one, if there are not enough water concentration around the cell, the cell shrivels up to have the same concentration as the outside by getting rid of water. Like this, osmosis helps cell to get balanced. Which makes our body balanced.
SELF EVALUATION / TEAM EVALUATION
Team) I think our team did really quick work with calculating the changes in the eggs. We didn't spend much time on them, but we did quick and correct measuring. The teamwork was really good, for example, when me and Sofia was working on getting the egg of from the cup, and washing them, Thomas got the paper towel and dried them. Also when I was measuring the circumference of the alcohol egg, other two did measure salty water egg's mass and the amount of the solution left. So I think that is why we didn't take long time to working on with measuring things, and take more time with observation the eggs, and have more deep think about it.
Self) I think I was doing well during the lab, but I was not understanding well about the osmosis IN the eggs, so it was kind of hard to work on putting them in the words. Also, the thing that I regret is, that I didn't use much class time to work on the blog post, so I was doing them at the last moment of the due date. :( I should pay attention more with working on the stuffs that I'm doing. Also I thought about the possible errors, even our group has the same result as the general results. Maybe we might lost more alcohol and salty water because we didn't cover the top of the cups. And I learned that the osmosis takes a place with two different concentrations, and it doesn't stop even the concentration become same.
