Okay kiddo, you know how when you push a swing it starts swinging back and forth? Well, sometimes in the world of electricity, things can start swinging back and forth too, and we call that swinging motion an "oscillation". Now, an oscillation usually happens when something like a sudden change or disturbance occurs in an electrical circuit, and the electricity starts bouncing back and forth between different parts of the circuit.
However, these bounces don't last forever, and eventually the electricity settles back to its normal state. We call this brief period of bouncing electricity a "transient". It's like when you jump on the trampoline - you bounce up and down for a bit, but eventually come back down to earth. In an electrical circuit, the transient can cause all kinds of problems, like causing a light bulb to flicker or a computer to reboot.
So, we try to prevent these transients by using things like circuit breakers and surge protectors. That way, if there's a sudden change or disturbance in the electrical circuit, these devices can help prevent the electricity from bouncing back and forth too much, and keep everything running smoothly.