Camera/Lens Technique: Fast and slow shutter speeds

I took two photographs of a fan using both a fast and slow shutter speeds. For the slow shutter speed i set the camera to ISO 400 f 5.6 and the shutter speed was 1/40. The fan is seen spinning and slightly blurred.

For the fast shutter speed i set the camera to ISO 400 F 8.0 and the shutter speed was 1/500. The speed is that fast that the fan blades are caught frozen. Something that the camera can do that the human eye cannot see.