It means the waves collides and constructive interference occurred.
<h3>Explanation:</h3>
If the two waves coming from the opposite direction collide with each other, there are two way of their interference.
Constructive interference: An interference which results in the increase in energy. And it is when crust of a wave comes on the crust of second wave.
Destructive interference: An interference which results in decrease in energy of the resulting wave and colliding waves cancel the result of each other.
Hence in experiment there will be constructive interference.
It seems that you have missed the given options for the given statement above. But anyway, here is the correct answer. <span>Pierce conducts an experiment in which waves collide in a way that the energy increases, which means that CONSTRUCTIVE has occurred. Hope this is the answer that you are looking for.</span>
