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Aim was to find out if how aldosterone retains water through manipulating salt levels. Backgroud research:
The background research basically states that aldosterone acts in the ascending limb of the loop of Henle and distal tubes located in the nephrons of kidneys. It actively changes the concentration gradient. Allowing water to be retained through osmosis.
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The hypothesis is as the sodium chloride concentration increases in the solution, the higher the increase in weight and the higher the increase in water level of the NaCl solution over 24 hours will be recorded. This is because of the fact that water moves from a low solute concentration to a high solute concentration through osmosis.
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Here are the set of materials used.
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This experiment is relatively low risk.
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The independent variable is the weight of sodium chloride I place in each beaker; the dependent variable are the change in water level, which is measured by a ruler and the change in weight of the solution, which is measured on the electrical scales. The controlled variables include limited evaporation by glad wrapping the apparatus, time taken per trial and the type of salt used. A control was set up where no salt was added to the beaker, any change in weight or water level would be used to adjust other solutions that have undergone osmosis. Looking at the model, the solution in the beaker represents the blood stream whereas I acted as the hormone aldosterone varying the amount of salt in the beaker. The water dyed red in the solution represents the filtrate traveling through the loop of Henle and distal tubes.
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The results from 3 trials were averaged and placed in a table. The results from the control have been accounted in the data. The fact that the NaCl solution in the beaker changed from clear to red indicates that osmosis has occurred.
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This graph shows a slightly increasing relationship where as the amount of salt in solution increased so did the increase in water level. (Next)
This graph shows that as salt concentration increases, the higher the increase in weight of the solution over 24 hours. (next)
From the results obtained a trend can be identified where as salt concentration increases, a higher change in water level and a higher increase in weight of the solution are recorded over 24 hours. From this we can say that more water exits the dialysis tubing as the salt concentration gradient increases.
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To explain this I’m going to share a little story of mine. I am actually the filtrate that is traveling through the loop of Henle. Here are my salt ions and these are my water particles. Apparently the receptors are saying there is a low blood volume and pressure. So as I go up the ascending limb of the loop of Henle, more aldosterone were sent out to actively transport salt into the outer medulla. (there goes my salt). The ascending limb is impermeable to water. As I travel up and reaches the distal convoluted tubes, me as the filtrate has a low solute concentration while the outer medulla has a high solute concentration. As a result my water particles will move along this concentration gradient into the outer medulla passively through osmosis. (there goes my water). This is how aldosterone retains water.
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The experiment is relatively valid as it satisfies the aim and is conducted under a controlled environment, except for the ambient temperature as it was conducted in a shared lab. A control was used to where its results were used to adjust the solutions that undergone osmosis.
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The results obtained were accurate as it matches published data and the theory of osmosis.
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It was relatively reliable as 3 trials were conducted and compared, and a clear trend is shown in each trial.

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It has a low precision as measuring with a ruler and marking the water level with a marker decreases precision.
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Lack of aldosterone can result in low