Cucumbers’ Mass and Volume in Different Substances
Problem: If cucumber slices are placed in water, ten percent sugar solution, and twenty percent sugar solution what will happen to the cucumber?
Independent variable: mass and volume of cucumber after being soaked for 24 hrs
Dependent variable: type of solution (water or sugar substance)
Control: the cucumber before being placed in the substance
Constant: amount of substance in each cup, how long the cucumbers in the water for, the plastic wrap on each cup
Hypothesis: If cucumber slices are placed in water, ten percent sugar solution, and twenty percent water solution, then the cucumber in water will be isotonic (have the same measurement), the cucumber in the ten percent sugar water
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will become hypertonic (have smaller measurement), and the cucumber in the twenty percent sugar solution will be very hypertonic (even smaller). This is because of the process of osmosis and how things travel on the concentration gradient. Materials: Lab apron Knife or scalpel Graduated cylinder Paper towels Metric ruler 20% sugar solution Marking pencil 10% sugar solution Tap water Small dishes Balance Aluminum foil/ plastic wrap Cucumber Procedure: Gather all materials With sharpie label the 3 cups; A just water, B 10% sugar solution, and C 20% sugar solution Cut cucumber into three semi even rectangles Measure and record each cucumbers volume and mass Fill each cup with the designated substance (in A fill 30mL of water, in B fill 30mL of 10% sugar substance, in C fill 30 mL of 20% sugar substance) Put one cucumber slice in each cup Using parafilm paper cover each cup so no evaporation comes out Let cucumber sit over night After twenty-four hours take out cucumbers and find the volume and mass of each Record and make conclusions Mass and volume of substances before and after being put in solutions: Cucumbers original volume Cucumbers original mass Cucumbers volume after soaking for 24 hrs Cucumbers mass after soaking for 24 hrs Water 1.5 cm³ 2.65 g 2.66 cm³ 3.1 g 10% sugar solution 2.26 cm³ 2.97 g 2.1 cm³ 2.5 g 20% sugar solution 1.36 cm³ 2.38 g 1.26 cm³ 1.5 g Analysis Questions: Other than the changes observed by our data, a few qualitative changes occur to the slices of cucumber after being soaked in the solution for 24 hours. The cucumber that had been immersed in water had occured to look larger. When doing our quantitative observations, we realized that it had infact gotten larger. The cucumber placed in the 20% sugar solution however, seemed to have decreased in size. Again, this qualitative observation was proved right by our quantitative data. The cucumber that was in the 10% sugar solution seemed to have not changed much after sitting in its solution for 24 hours. Although in the quantitative observations, it is shown that it got smaller, but very slightly. Before putting the cucumbers in the solution, we measured their volume and mass. The cucumber placed in water had a volume of 1.5 cm³ and a mass of 2.65g. After leaving the cucumber in water for 24 hours its volume and mass had both increased. The volume was now 2.66 cm³ and the mass was 3.1g. This shows that the cucumbers change in size was relative to its mass. As it absorbed more water, the more volume and mass was increased. In the lab, when a cucumber was placed in an all water solution, the mass was enlarged. The original mass was 2.65g, and after 24 hours it was 3.1g. When the concentration of water went down and the sugar concentration up, the mass decreased. For example, in the 20% sugar solution, the original mass was 2.38g and after being soaked for 24 hours it was 1.5g. This shows that the more water concentration, the larger mass. The sugar concentration in water in which a cucumbers mass will not change is 5%. This is because on the chart, the cucumber in all water was too much, making it hypotonic. Although, the 10% sugar solution dried out the cucumber. To make the cucumber isotonic, you have to do a median of the two. There are many terms that relate to chapter three of what we learned in science. For example, hypertonic, hypotonic, and isotonic. These terms relate to the amount of water concentration in and outside a cell. In this lab, the cucumbers showed all these terms. In the complete water, the cucumber became hypotonic, and in the 10 and 20% solutions the cucumber became hypertonic. When trying to figure out how to make the cucumber not change, isotonic was used. Conclusion The purpose of this lab was to see the effects of cucumbers after being soaked in different water to sugar solutions.
It was stated in the hypothesis that, “If cucumber slices are placed in water, ten percent sugar solution, and twenty percent water solution, then the cucumber in water will be isotonic (have the same measurement), the cucumber in the ten percent sugar water will become hypertonic (have smaller measurement), and the cucumber in the twenty percent sugar solution will be very hypertonic (even smaller). This is because of the process of osmosis and how things travel on the concentration gradient.” To test the hypothesis, three cucumbers were placed in three different solutions after being tested for their volume and mass. One solution held only water, another had 10% sugar, and the last had 20% sugar. After letting the cucumbers soak in each solution, their volume and mass was tested again. As shown in the table, the solution with only water had made the cucumber hypotonic. The volume was increased .16 and the mass increased .36g. In the 10% and 20% sugar solutions, the cucumber became hypertonic. The volume and mass of each cucumber had decreased. In the 10% solution, the volume went down by .16 and the mass went down .47g. In the 20% sugar solution, the volume decreased by .10 and the mass by .9g. The data collected from the lab proved our hypothesis was correct. One way to improve this lab would be to make sure the cucumbers were all the exact same size. This would make the data more accurate and easier to
read.
One thing that needs to be kept constant is the amount of water for each temperature. If the amount of water is varied that means that the data would not be that reliable and easy to look at. This can be kept constant by measuring how much water by looking at the meniscus. Another constant has to be the Alka-Seltzer tablets. This has to be kept constant because there are many different Alka-Seltzer tablets like there are ones that are citrus flavored and there are ones that treat your flu.
The data we gathered was tested to be as accurate as possible. Our prediction on the solvents did not support our data that we collected. The cause of this could be due to human error when washing the beets or the cutting of the beets. The beets were not perfectly cut the same size, so some beet pieces were bigger than others which can affect the final the final result. We followed each step and followed the time limits cautiously. I can say if we were to redo the experiment our results would be similar because we would attempt to do the experiment as close as we did the first
Investigating the Water Potential of Celery Cells Aim = == I will be investigating the water potential of celery and to find out which solution will be isotonic with the celery cells, in other words equilibrium between the two no water will leave the cell, or enter. I will do this by following this method. Method 1.
The materials my group used were three identical plastic cups, four gummy bears of the same color, one plastic spoon, one roll wax paper, one sharpie marker, one roll plastic wrap, one graduated cylinder, 25 mL super saturated salt solution, 25 mL distilled water, 25 mL 80% sugar solution, and one 12 inch ruler. The procedure my group made follows these steps.
Osmosis in Potato Tubes Osmosis: Osmosis is the movement of water molecules through a semi-permeable membrane from a high concentration to a low concentration. Diagram: [IMAGE] [IMAGE] Aim: To see the effects of different concentration of sugar solution on Osmosis in potato tubes. Key factor: In the investigation we change the sugar solution from: 0%-10%-20%-30%-40%-50% this is the independent variable; the dependant variable is the change in mass. Prediction: I predict that all the potato tubes in pure water or low concentration sugar solution will swell because water enters their cells by osmosis.
So the experiment will be based upon the movement of water. The first potato chip will be placed in a zero percent solution. I believe that this will increase the mass. I believe this because the zero percent solution has a lower concentration than the cell sap inside the potato. The potato takes on the water through osmosis and the cell pushes out from inside the cell making it swell and become more rigid.
To make the test fair I will use the same amount of water and the leaf
To investigate the osmotic effect of changing the concentration of sucrose solution; distilled water, 20% sucrose solution, 40% sucrose solution, 60% sucrose solution on the change in mass of potato cylinder after 30 minutes of being in solution.
At point A the graph shows that no change in mass, of the potato, would have have occurred had we used a 0.2 (m) sucrose solution. This suggests that the concentration of water inside the potato would have been equal to the solution outside the potato. At point B (plain water), there is no indication that the cell is increasing in mass. This is because the cell is fully turgid and no more water can enter.
However, the solution could be more water than salt so the water from the solution could be more concentrated than the water inside the potato cells. If so then In theory the water in the solution should diffuse into the potato. cells and increase in mass. Apparatus: Potato to perform the experiment on. Thin metal tube to cut potato chops with.
If we put the potatoes in different concentrations of seawater (0%, .4%, .8%, 1.2%, 1.6%, and 2%) then the potato put in the highest concentration of seawater (2%) will begin to discolor and fall apart while the potato put in the lowest (0%) concentration of seawater won’t discolor and fall apart because the seawater with the 2% concentration will diffuse into the potato causing it to break down and discolor faster than the potato in the lower concentration of seawater.
This is because the water molecules pass from a low concentration to a high concentration, (in the potato chip). Therefore, the chips in low concentrations will gain mass and have a greater length height than in higher concentrations such as 1molar of sugar solution. If there is no gain or loss in height or mass then these will be the isotonic points of the potato cells. The isotonic point is where the cells are not increasing or decreasing in size and is known to be in a state of equilibrium. Apparatus: 1.
4. Put each group of potato discs in one of the 6 test tubes and watch
The practice of using animals for testing has been a controversial issue over the past thirty years. Animal testing is a morally debated practice. The question is whether animal testing is morally right or wrong. This paper will present both sides of this issue as well as my own opinion.
Prediction I think that when the potato is placed in distilled water the potato mass will increase. This is because water, has, if pure, a weaker concentration than the potato, and the water molecules move in through a partially permeable membrane by osmosis. If the potato is in a high concentration salt solution, the potato mass will decrease because the potato is less concentrated than the salt solution, and the water will move through the partially permeable membrane into the stronger solution. However, if the potato mass stays the same after the experiment, this means that the water/salt solution and the potato must be of equal concentration.