We just learned about the Negative Feedback.
Another part of machine science is Hydraulics.
This means using the power of water to move machines.
The science of hydraulics goes back thousands of years, and can be as simple as just a water wheel that is using the power of a river to turn the wheel.
Any system that uses water to move something is using hydraulics.
(from: wikipedia - hydraulics)
Kid Facts - Blast from the past: Ariane