I will present results of molecular dynamics simulations of hemispherical hydrophobic pockets remaining in direct contact with water. The considered pockets of three different sizes represent simple models of nonpolar cavities often found in proteins' binding sites where they are important for hydrophobic interactions with ligands. A detailed analysis of solvent behaviour reveals significant density fluctuations inside the pockets resulting from cooperative movements of individual water molecules. \\ \noindent I will also consider a process of translocation of methane molecule from bulk solvent into the pockets and discuss the obtained potentials of mean force. Their analysis in the light of observed changes in water distribution around the interacting hydrophobic