Winogradsky Column After one week (Group A)

In the picture we can not see to many differences between both columns.

We think that the black color in both columns are from the combination of iron and sulfur.

On the other hand, we think that they look similar because the column that is in the sunlight doesn’t need it as energy source. 

 

The left picture is the column in darkness and the right picture is the column exposed to the light.