  We consider a flat cosmological model with a free massless scalar field and
the cosmological constant $\Lambda$ in the framework of loop quantum cosmology.
The scalar field plays the role of an intrinsic time. We apply the reduced
phase space approach. The dynamics of the model is solved analytically. We
identify elementary observables and their algebra. The compound physical
observables like the volume and the energy density of matter field are
analysed. Both compound observables are bounded and oscillate in the
$\Lambda<0$ case. The energy density is bounded and oscillates in the
$\Lambda>0$ case. However, the volume is unbounded from above, but periodic.
The difference between standard and nonstandard loop quantum cosmology is
described.
