Molecular vibrations refer to the oscillations of atoms within a molecule. These vibrations occur as atoms move closer together and farther apart, similar to how a spring compresses and stretches. Each type of bond between atoms has a specific frequency at which it vibrates, influenced by factors like bond strength and atomic mass. These vibrations can be detected using techniques such as infrared spectroscopy and Raman spectroscopy. By analyzing the vibrational frequencies, scientists can gain insights into the molecular structure and dynamics of substances, aiding in fields like chemistry and material science.