Build a windmill with adjustable vanes. You will discover that in order to make it work, the vanes have to be adjusted just right to turn fast enough to work. Then apply that wind power to make it work. How? By making it lift weight, you can observe just how much power output it can produce. You will discover the problem of scale and its limitations but the potential is there.
Understand the gearing needed to manage the lift. About the relationship between speed and power. It's not necessarily intuitive.
