Final Post~

Group 4 Project

The Procedure:

First we calibrated the dissolved oxygen probes using the sodium sulphate solution given to us. We then went to different parts of Pedder Bay and measured the dissolved oxygen in the water. We measured the dissolved oxygen directly from the bay as this would reduce the error of the dissolved oxygen in the water. At the each spot, we also collected a sample of the water. Using the polorometer we measured how much light was able to pass through each sample. We got the values in volts. The higher the voltage the higher the turbidity.

Conclusion: According to the graph shown above there seems to be an inverse relationship between the turbidity and the amount of dissolved oxygen levels in the water samples. However, we cannot come to a vary strong conclusion because other factors may have effected the results.

Error: There are other variables that may affect the ammount of dissolved oxygen. This includes water temperature, wind speed, depth, etc. Trying to keep these under control is very hard. A method that could be tried could be to first collect the samples and then measure that dissolved oxygen in a place where these things are constant. However, the problem with this is that the amount of dissolved oxygen changes when you take the sample. To avoid this, the samples could be left open for about day and then measured.

Problems faced: We were unsure of how to use equipment, therefore we wasted a lot of time and effort. Because of this were able to collect only 7 samples. However, from these samples three had the same amount of dissolved oxygen, so we decide to ignore them. This affected our investigation.

PIcture

This is what "Mark Wheens Invention" looks like

Our PLan!!!

In the beginning of this process, our intention was to test the amount of Algae in various locations in the Ocean. As we discussed our intentions with various teachers, we realized that measuring the amount of algae would be to difficult. Therefore we have changed our topic question. Now, we are taking samples from various areas in the ocean! We are going to investigate how the turbidity affects the amount of dissolved oxygen in the samples. We are going to use Mark Wheen's invention- which uses an LDR and an LED to measure the turbidity in the sample.

We have all agreed upon this method. It seems simple and effective.

We have tested this mechanism and the experiment seems to have been successful.

We will take samples from more locations before Saturday in order to maintain an organized schedule.