We can observe processes that rely on lack of observation in the microscopic world. Look up the one-slit and two-slit experiments[0]. In the two-slit experiment, we don't observe which slit the photon takes, but we can observe the interference pattern on the screen.
The two-slit experiment works with photons, but not with bullets, or cars, or baseballs.
The two-slit experiment works with photons, but not with bullets, or cars, or baseballs.
[0]: http://en.wikipedia.org/wiki/Two_slit_experiment