Zoetrope animations are not visible with the naked eye.
There needs to be an interval at the frequency of the number of frames.
To view the animations you will need a stroboscope or a shutter speed camera.
-Stroboscope for iphone/ipad:
-Stroboscope for android:
It takes some adjustment, as each animation has different frame rates, but you will see it happen as you higher or lower it. Most work around 10-15 fps at 33rpm.
Shutter speed camera for iphone/ipad
Filmic Pro also has an android version.
Filmic pro is not free but has a lot of options and control.
The shutter speed cameras work best with lots of light.