How will you prove that air supports burning?

Explanation

Step I: Two shallow containers are taken and burning candles are fitted into it.
Step II: Now, water is filled in the container at two different levels.
Step III: Both the candles are then covered with glass.
Step IV: After sometimes, we observed that the candles having less water in its container lights off.
This happened because the container having more water contains more oxygen and therefore it burnt for more time. Thus, it is proved that air supports burning.