Read the following description of Tube #2:

Question

Tube #2 contains:

Bromothymol blue (BTB)
Carbon dioxide
Exposed to light
Elodea present
Initially yellow-green in color
After 24 hours, Tube #2 is now blue in color. In 1-2 sentences explain why.
make it simple and like a kid wrote it

Answer 1

Tube #2 changed from yellow-green to blue because the Elodea plants used the sunlight to make oxygen and take in the carbon dioxide. The bromothymol blue changed color because there was less carbon dioxide in the water!