system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Let's say some evil mad scientist actually blows up the moon. What exactly would happen to our oceans?

Would the water just go everywhere or what? 

Thought inspired by Chief-Inspector Dreyfuss and his doomsday device.
gpt
It depends what is entailed by blowing up.

In the scenario where the moon is just smashed into many tiny pieces, the most likely result is that depending on the force of the blast, the pieces would either hang around in the same spot or drift around into a lumpy ring around the earth for a while. This ring wouldn't last long, as the biggest chunks of moon would quickly pick them up and the whole thing would reform again. Some of the chunks would likely be blown out into solar orbit, and some would smash into the Earth causing big problems down here. Nobody would be thinking about the tides. The Moon is over 1700 kilometers across. A single 10 kilometer chunk hitting us would be a mass extinction event.

If magically the Moon just vanished from the sky, the tides would be substantially reduced in height. The Moon accounts for most of their variability, but the Sun is also part of it. So we would have much weaker tides, about a third of what they are now.

But still no one would really care about that. One of the Moon's convenient jobs for us is to keep our axis stable. The Earth maintains an axial tilt pretty close to 23.5 degrees all the time. It wobbles a bit over thousands of years, but not much. Without the moon, our axis could move all over the place, turning the poles straight up and down, eliminating the seasons, or, much worse, turning us 90 degress so our poles face the sun, giving each hemisphere a 6 month long day and 6 month night. This would totally redefine the climate and be the end of life as we know it. During "noon" one side of the Earth would be roasted while the other froze. Our equator would be the only place with a temperature friendly to us, but unfortunately the temperature gradient would cause constant superhurricane force winds at the equator.

I guess TL;DR, we need to be more appreciative of the Moon.