What does an increase in molecular vibration indicate about temperature?

An increase in molecular vibration is directly related to an increase in temperature. When temperature rises, the thermal energy of a substance increases, causing the molecules to move more vigorously. This increased kinetic energy manifests as higher vibrational motion among the molecules. Therefore, as the molecular vibration intensifies, it serves as an indicator that the temperature of the substance is also rising.

This understanding stems from the kinetic molecular theory, which posits that the temperature of a substance reflects the average kinetic energy of its molecules. As the kinetic energy increases due to higher temperatures, so does the vibration of the molecules within that substance.