Our DP student Octavi Galli, explains us his Chemistry experiment that will be the basis of his Internal Assessment (IA).
«Today I have been working on my Chemistry Internal Assessment which is about the determination of dissolved oxygen in river water.
In the last years, global warming has had an impact in all types of ecosystems, including aquatic ones. Oxygen is essential for the majority of aquatic organisms in rivers. Thus, I’m focusing on finding a correlation between temperature and the level of dissolved oxygen in a water sample from the Congost river.
I’m doing this following the Winkler’s method, which is a procedure involving the fixation of oxygen in water and then, titrating the sample with sodium thiosulfate (Na2S2O3), in order to calculate the volume of dissolved oxygen in the sample by reverse stoichiometry.
Today I’ve finished samples from one temperature (10 °C) and in the next days I will do the same with other temperatures.»
by Octavi Galli (DP Student)
We can see on the photos, another students performing the IA-Biology.

