In order to find the answer to our experiment, we need to collect the data of the percentage of eggs that hatched over a specific amount of time. Although, before we collect our data we have to form a procedure. An important note in our procedure is that the salinity of the water – being the independent variable – will affect the number of eggs that hatch, which is the dependent variable. The first step is to pour 26 millilitres of saltwater into one petri-dish; 26 millilitres of brackish water into the second petri-dish; a mixture of 13 millilitres of saltwater and 13 millilitres brackish water into the third petri-dish.
Each petri-dish will have the same amount of water to ensure that the amount of water will not affect the procedure. Second, we place double sided tape on each dish and lightly brush the eggs on the pieces of tape; the tape will replicate the cysts that are in the brine shrimps’ natural habitat. Third, we count the number of eggs in each dish, using a light microscope. We count the number of eggs to calculate the percentage of hatched eggs at the end of the procedure. The third step is an example of quantitative data because numbers are used to create data. Fourth, pour the specified water in its dish, close it and label the type of water that the dish contains. It is very important to label each petri-dish to ensure that the results are correct. Once accomplished, repeat the fourth step for the remaining two dishes.
Continually count the number of eggs that hatch in each dish over the following week to see if any of the eggs died. The number of hatched eggs in each dish will establish how the salinity of water affects the number of eggs that hatch. Four constant groups in this procedure are the amounts of water in each dish, the type of eggs that we monitor, the replica we used of the cyst and the duration of time we monitored the eggs. A constant is a variable that remains the same throughout the experiment. The control group would be the brine shrimp in freshwater because there is no salt found in the water. The control group will act as a baseline to show us how the salinity of the water affects the brine shrimp.Our claim was that the higher the salinity, the higher the percentage of hatched eggs.
After a full week of analyzing the eggs, 17% of the eggs hatched in freshwater; 82% of the eggs hatched in the saltwater; 41% of the eggs hatched in the brackish water, as shown in Figure 1 and Table 1. The evidence corresponds with our claim because the higher the salinity was in the solution, the greater the percentage was of hatched eggs. The salinity affected the percentage of hatched eggs because of a process called osmosis. Osmosis is the diffusion of water across a selectively permeable membrane from a high concentration to a low concentration (1). When not enough salt is added to the solution, the solution is hypertonic.
When a solution is hypertonic, water secretes into the brine shrimp eggs and kills them. However, when the salinity in the solution increases, the eggs will absorb less water, allowing the eggs to hatch (2).