“Today, we’re learning about ripples. Different objects cause different wave and ripple patterns,” the teacher said. “What is the only way to stop a ripple, according to the laws of physics?”

“Help it dissipate to its smallest energy state,” a student answered.

“Excellent. How do we do that?”

“Calm the pond,” Charlie answered.

“That’s right. You need to calm the pond somehow. So how do we do that?”

“You need to cause something to happen that provides an equal and opposite reaction?” Bernie said, unsure.

“Exactly! What happens when you have two forces, equal and opposite, colliding?”

“They cancel each other out!” a student at the front of the class called out.”