Egg Osmosis Lab
Purpose To explore transport of materials in three semi-permeable membranes: dialysis tubing, eggs, and onion cells.
Background Information 1. Diffusion is the movement of solutes from high to low concentration. Osmosis is the movement of water from low to high concentration. Both refer to movement in/out of a cell, but osmosis refers specifically to water.
2. Isotonic, hypertonic, and hypotonic all refer to the comparison of concentrations of solutes in verses out of the cell. Isotonic is when the concentration in the cell is the same as the concentration outside of the cell. Hypertonic is when the concentration outside of the cell is greater than inside. And hypotonic is the opposite; the concentration outside of the cell is less than inside of the cell. …show more content…
Hypothesis Procedure A: The dialysis tubing will allow the iodine solution in, and some of the starch solution will be let out
Procedure B: After the egg is placed in vinegar, the width will be larger and the mass will be similar to the original.
After the egg is placed in molasses, the width will be similar, and the mass will be larger. After the egg is placed in water, the mass and width will be larger.
Procedure C: The onion in salt water will look “parched” compared to the onion in distilled water. The whole cell will be smaller and shriveled.
Materials Dialysis tubing, starch solution, iodine solution, raw egg, vinegar, molasses, onion, and salt water.
Procedure See lab procedure
Observations Procedure A: At the beginning of the procedure, the iodine solution in the beaker was slightly yellow, and the starch solution in the dialysis tubing was milky. After about an hour, the inside of the dialysis tubing was very blue and the liquid in the beaker was clear and colourless.
Procedure B:
Egg
Starting Weight
Vinegar
Molasses
Water
Weight
57.92 g
77.98 g
53.38 g
85.51 g
Width
13.5 cm
15.6 cm
13.6 cm
15.5 cm
Description
- hard, round, white
- squishy, slightly clear,
round
- brown, shriveled, squishy
- light brown, slightly clear, round, squishy
Procedure C: The cell membranes of the onion cells in the salt solution were slightly detached; there was a gap between the cell membrane and cell wall. The cell membranes of the onion cells in the distilled water were still attached to the cell wall; there was no gap.
Conclusion Procedure A: The colour changed to purple, which indicated that the iodine solution was let in the dialysis tubing. This means my hypothesis was partially right, but no starch solution was let out of the dialysis tubing.
Procedure B: Both the weight and the width of the egg got larger in vinegar, smaller in molasses, and then larger again in water. My hypothesis for the vinegar was correct for the weight, but not the width. For the molasses, my hypothesis for the weight and width were incorrect. But my hypothesis for the water was correct.
Procedure C: The cell membrane of the onion cells in the salt solution were detached from the cell wall, where the cell membrane of the onion cells in the distilled water were attached to the cell wall. This means my hypothesis was slightly correct. But the whole cell didn’t shrivel, just the cell membrane.
Discussion Procedure A had a major colour change. When the inside of the dialysis tube changed to purple, it indicated that iodine was let into the tube. There was no colour change in the beaker, which means that no starch solution was let out. The iodine was let in because they are just small ions that can easily pass through. But the starch wasn’t let out because it is a big complicated molecule that can’t fit out of the dialysis tube. No errors were made during the experiment. If the experiment were to be done again, I would have made the beaker more important for us to watch so we could see the changed as they happened and not just after the fact. I wonder what size a molecule has to be to be considered too big to pass through the cell membrane. Procedure B had three separate changes that showed osmosis. When the egg was placed in the vinegar, the width and weight of the egg increased. This was because the vinegar was hypotonic to the egg and allowed water into the egg to even out the concentrations. When the egg was placed in the molasses, the width and weight of the egg decreased. This was because the molasses was hypertonic to the egg and allowed water out of the egg to even out the concentrations. When the egg was placed in water, the width and weight of the egg increased. This was because the water was hypotonic to the egg and allowed water into the egg to even out the concentrations. One mistake that was made was that the egg was not fully covered in molasses and that could have affected how much water went in/out of the egg. If the experiment were done again, I would have added more vinegar, molasses, and water to the beaker to make sure the egg was fully submerged. I wonder why what other liquids would have been hypertonic to the egg, just like molasses?
Procedure C had a small, but significant change between the two onion cells. The onion cell in the salt water had a few cells where the cell membrane was separated from the cell wall. This happened because the salt water was hypertonic to the cell. Water rushed out of the cell to balance out the concentrations; therefore causing the cell membrane to “shrink”. The onion cell in the distilled water had no visible changes. This happened because the distilled water was isotonic or slightly hypotonic to the cell and it stayed the same, or swelled up a little bit, because water was let in. One mistake that was made was that the methylene blue stain didn’t go all the way under the slide so it was hard to see the cells. The onion cell in the salt water had only a few cells that had cell membranes apart from the cell wall, making it hard to find a good example of what happened. If the experiment were done again, I would have added more salt water to try and allow more cells to react to the conditions. I wonder if the cells in distilled water changed size from when they were on the onion, to when they were prepared on the slide? The distilled water should have been hypotonic to the cell, but there was no “dry” onion we could compare it to.
Discussion Questions
The dialysis tubing was rinsed so that there was no starch solution that may have been spilt in the side. That could have skewed the results by leading us to believe that some of the starch solution went out of the tubing.
If the starch solution was in the beaker and the iodine solution was in the dialysis tubing, the liquid in the beaker would have become dark and the liquid inside the dialysis tubing would have been clear.
The dialysis tubing is semi-permeable because it let the iodine inside, but the starch was not let out. We know this happened because of the colour change in the tubing.
The vinegar dissolved the calcium carbonate because vinegar is an acid and calcium carbonate is a base. When they were placed together, they formed a neutralization reaction. The acetic acid breaks the shell into calcium ions and carbonate, which forms carbon dioxide.
The vinegar was a hypotonic solution compared to the egg. This was evident because water entered the egg and made it balloon up.
The molasses was a hypertonic solution compared to the egg. This was evident because the water from inside the egg exited the egg and made it shrivel.
The water was a hypotonic solution compared to the egg. This was evident because the water entered the egg and made it balloon up.
The salt solution was hypertonic to the onion cell. This was evident because water exited the cell to dilute the salt water, therefore detaching the cell membrane. The distilled water was hypotonic to the onion cell. This was evident because water entered the cell and it kept it’s shape.
Vegetables are sprinkled with water because water is hypotonic to the vegetables. This allows more water to enter the cells than what can escape. Therefore the vegetables are crunchy and firm.
When roads are salted, the plants along the roadside will shrivel up. This is because the salt is hypertonic to the plants, and water is let out to try and balance the concentrations.
Background Information 1. Diffusion is the movement of solutes from high to low concentration. Osmosis is the movement of water from low to high concentration. Both refer to movement in/out of a cell, but osmosis refers specifically to water.
2. Isotonic, hypertonic, and hypotonic all refer to the comparison of concentrations of solutes in verses out of the cell. Isotonic is when the concentration in the cell is the same as the concentration outside of the cell. Hypertonic is when the concentration outside of the cell is greater than inside. And hypotonic is the opposite; the concentration outside of the cell is less than inside of the cell. …show more content…
Hypothesis Procedure A: The dialysis tubing will allow the iodine solution in, and some of the starch solution will be let out
Procedure B: After the egg is placed in vinegar, the width will be larger and the mass will be similar to the original.
After the egg is placed in molasses, the width will be similar, and the mass will be larger. After the egg is placed in water, the mass and width will be larger.
Procedure C: The onion in salt water will look “parched” compared to the onion in distilled water. The whole cell will be smaller and shriveled.
Materials Dialysis tubing, starch solution, iodine solution, raw egg, vinegar, molasses, onion, and salt water.
Procedure See lab procedure
Observations Procedure A: At the beginning of the procedure, the iodine solution in the beaker was slightly yellow, and the starch solution in the dialysis tubing was milky. After about an hour, the inside of the dialysis tubing was very blue and the liquid in the beaker was clear and colourless.
Procedure B:
Egg
Starting Weight
Vinegar
Molasses
Water
Weight
57.92 g
77.98 g
53.38 g
85.51 g
Width
13.5 cm
15.6 cm
13.6 cm
15.5 cm
Description
- hard, round, white
- squishy, slightly clear,
round
- brown, shriveled, squishy
- light brown, slightly clear, round, squishy
Procedure C: The cell membranes of the onion cells in the salt solution were slightly detached; there was a gap between the cell membrane and cell wall. The cell membranes of the onion cells in the distilled water were still attached to the cell wall; there was no gap.
Conclusion Procedure A: The colour changed to purple, which indicated that the iodine solution was let in the dialysis tubing. This means my hypothesis was partially right, but no starch solution was let out of the dialysis tubing.
Procedure B: Both the weight and the width of the egg got larger in vinegar, smaller in molasses, and then larger again in water. My hypothesis for the vinegar was correct for the weight, but not the width. For the molasses, my hypothesis for the weight and width were incorrect. But my hypothesis for the water was correct.
Procedure C: The cell membrane of the onion cells in the salt solution were detached from the cell wall, where the cell membrane of the onion cells in the distilled water were attached to the cell wall. This means my hypothesis was slightly correct. But the whole cell didn’t shrivel, just the cell membrane.
Discussion Procedure A had a major colour change. When the inside of the dialysis tube changed to purple, it indicated that iodine was let into the tube. There was no colour change in the beaker, which means that no starch solution was let out. The iodine was let in because they are just small ions that can easily pass through. But the starch wasn’t let out because it is a big complicated molecule that can’t fit out of the dialysis tube. No errors were made during the experiment. If the experiment were to be done again, I would have made the beaker more important for us to watch so we could see the changed as they happened and not just after the fact. I wonder what size a molecule has to be to be considered too big to pass through the cell membrane. Procedure B had three separate changes that showed osmosis. When the egg was placed in the vinegar, the width and weight of the egg increased. This was because the vinegar was hypotonic to the egg and allowed water into the egg to even out the concentrations. When the egg was placed in the molasses, the width and weight of the egg decreased. This was because the molasses was hypertonic to the egg and allowed water out of the egg to even out the concentrations. When the egg was placed in water, the width and weight of the egg increased. This was because the water was hypotonic to the egg and allowed water into the egg to even out the concentrations. One mistake that was made was that the egg was not fully covered in molasses and that could have affected how much water went in/out of the egg. If the experiment were done again, I would have added more vinegar, molasses, and water to the beaker to make sure the egg was fully submerged. I wonder why what other liquids would have been hypertonic to the egg, just like molasses?
Procedure C had a small, but significant change between the two onion cells. The onion cell in the salt water had a few cells where the cell membrane was separated from the cell wall. This happened because the salt water was hypertonic to the cell. Water rushed out of the cell to balance out the concentrations; therefore causing the cell membrane to “shrink”. The onion cell in the distilled water had no visible changes. This happened because the distilled water was isotonic or slightly hypotonic to the cell and it stayed the same, or swelled up a little bit, because water was let in. One mistake that was made was that the methylene blue stain didn’t go all the way under the slide so it was hard to see the cells. The onion cell in the salt water had only a few cells that had cell membranes apart from the cell wall, making it hard to find a good example of what happened. If the experiment were done again, I would have added more salt water to try and allow more cells to react to the conditions. I wonder if the cells in distilled water changed size from when they were on the onion, to when they were prepared on the slide? The distilled water should have been hypotonic to the cell, but there was no “dry” onion we could compare it to.
Discussion Questions
The dialysis tubing was rinsed so that there was no starch solution that may have been spilt in the side. That could have skewed the results by leading us to believe that some of the starch solution went out of the tubing.
If the starch solution was in the beaker and the iodine solution was in the dialysis tubing, the liquid in the beaker would have become dark and the liquid inside the dialysis tubing would have been clear.
The dialysis tubing is semi-permeable because it let the iodine inside, but the starch was not let out. We know this happened because of the colour change in the tubing.
The vinegar dissolved the calcium carbonate because vinegar is an acid and calcium carbonate is a base. When they were placed together, they formed a neutralization reaction. The acetic acid breaks the shell into calcium ions and carbonate, which forms carbon dioxide.
The vinegar was a hypotonic solution compared to the egg. This was evident because water entered the egg and made it balloon up.
The molasses was a hypertonic solution compared to the egg. This was evident because the water from inside the egg exited the egg and made it shrivel.
The water was a hypotonic solution compared to the egg. This was evident because the water entered the egg and made it balloon up.
The salt solution was hypertonic to the onion cell. This was evident because water exited the cell to dilute the salt water, therefore detaching the cell membrane. The distilled water was hypotonic to the onion cell. This was evident because water entered the cell and it kept it’s shape.
Vegetables are sprinkled with water because water is hypotonic to the vegetables. This allows more water to enter the cells than what can escape. Therefore the vegetables are crunchy and firm.
When roads are salted, the plants along the roadside will shrivel up. This is because the salt is hypertonic to the plants, and water is let out to try and balance the concentrations.