Project Report: Temperature, Salinity and the Currents of the Ocean

For this small experiment, our class group used a simple procedure of integrated water cycles to other containers to simulate the water currents of an ocean. The purpose of this experiment was to determine the difference between how the changes in temperature affected each container, and, using examples, show how each set of containers acted based on their temperature and salinity levels.

Making sure that the temperature of the large container was measured out to room temperature, and could hold water up to at least half of it's top, we carefully filled two small bottles with water. One bottle contained water that was heated to 40.3 degrees Celsius and had a large amount of salt inside of it, while the other contained water that was heated to 9.5 degrees Celsius and only contained a moderate amount of salt.
We then applied different types of food color dye to the two bottles of water before releasing it into the large container, in order to keep track of which one was which. The warmer water with a higher salt level was dyed red, and the cooler water with a lower salt level was dyed green, to show the two different contrasting colors mixing together.
Finally, the actual experiment began. Using our thumbs to cap off the bottles, we dropped them into separate parts of the large container we filled up, and released the liquid out into the water. For the first trial, we noticed that the warmer water (colored red) moved to the top of the container, while the colder water (colored green) stayed at the bottom and didn't move all that much.

We conducted several different versions of this experiment, each one with a different level of salinity. For the second go around, the red water got 3 grams of salt and the green water .75 grams. This time, we observed that both the colors stayed at the bottom, but red leaked out faster and moved in closer towards green. Being a higher density, when red and green moved towards each other, the red penetrated the green's territory first when they both overlapped. It was the same on the third try as well.

This test was created to see if the colors would respond to being put in the same container together, and whether or not their salinity levels would keep them apart or combine them together. In the end, 
what we ended up observing was that when all of the bottles filled with colored water were placed in the bottom of the container, the liquid initially stayed on the bottom. This is because warmer water with low salinity initially wants to rise, while the cooler water with high salinity descends, so in the process both substances are temporarily in a struggle for dominance, creating a cancelling effect. However, their behaviors varied from each different test because each time, their salinity level was different. With all tests, the higher salted would sink and the warmer water would rise, thus cancelling each other out. Alternatively, the lower salt level would rise but the colder water would sink, thus also creating a cancellation process.

In real world situations, the actual water currents that push toward the Atlantic can be strongly affected by both their density and salinity levels. At high latitude, water with a higher density can become entrenched in the ocean basins. This is due to Thermohaline circulation, a piece of the larger scale ocean circulation system relating to temperature and salt content, and it serves to determine the density of sea water. A thermonucline area can create rapid change in the temperature of the ocean it is contained in. 

Water can become more dense depending on it's temperature decreasing or the decreasing of it's salinity. Water can sometimes gain different changes, like a pynocline (change in density) or a halocline (change in salinity). Because of these changes, lower density water will stay above higher density water, much like when the red water went on top of the green water in the experiment, waters that are the same density then they stay at the same level as seen in the third experiment. In this case, a combination of the balance of the salinity of a water system and the temperature of one serves as the determination of how dense a certain area or substance of water is.