"The frog had been hanging on a wire of copper; and it had been the metal of our knife which had sent a strange power through the brine of the frog's body." (Rand 52)
"We swung our fist through the windowpane, and we leapt out in a ringing of glass" (Rand 75)
"I stand here on the summit of the mountain. I lift my head and spread my arms. This, my body and spirit, this is the end of the quest." (Rand 94)
This is when Equality 7-2521 is in his secret tunnel, experimenting on a frog when the copper and metal knife create electricity. This is a vital part of the book, because this is what starts his revolution. Electricity is the reason so many other events take place.
Equality 7-2521 is showing the Scholars his "discovery" of electricity. The Council orders that he be locked up for going against the law and finding something from the forbidden times. He then breaks the window and flees to the forest. This is the climax of the story and makes a foundation for where he ends up in the end.
Liberty and Equality end up together in a house in the Uncharted Forest surrounded by mountains. This is at the very end when Equality becomes happy and is ready to restart the world like it once was. Ending the story with him knowing how to speak correctly with "I" instead of "we," and finding the sacred word is "ego."