Where did the acid in the tanks come from?

Today we got our first taste of the Scientific Process.

• Our class looked at using an indicator to get more information about something we're studying. In our case, we're studying aquatic environments. We used BTB to determine if acid was present in the aquariums we were observing.
• This forced us to think about the variables that may have caused the acid to occur. We considered the fish food, water source, algae, bacteria, fish waste, fish and plants.
• Then, I challenged you to consider which of these variables could have caused the acid. We narrowed it down to plants and fish. These could be called organisms.
• So, each group conducted a controlled experiment. Everything was the same, or controlled, except for the type of organism in the water. The organism was the manipulated, or changed, variable.

The results are indicated in the photo. Remember that when the BTB remains blue, there's no acid. When it begins to turn green-to-yellow there's more acid in the container.

Science Journal Entry

-Take some time in your journal to write the question down and to answer it in your journal. Don't forget to number and date the page.

Which organism created the most acid? How do you think this organism created the acid in the water?

What was the question that motivated us to conduct a controlled experiment?