This experiment is uncontrolled because two different masses of substance A are used.
Explanation:
A controlled experiment is a structured experiment aimed at testing a particular observation or observations. The setup of a controlled experiment helps to determine the reason why a particular observation occurs and what must have led to it.
In the experiment highlighted above, different masses of a substance were used, they were heated to different temperatures. The set up does not show any correlation between the masses of substances heated and the temperatures. It is even difficult to try to predict the hypothesis for this kind of experimental set up. All the variables in play can best be assumed to be independent of one another.
