Assessment and Qualifications Alliance (AQA) GCSE Physics Practice Exam 2026 - Free Physics Practice Questions and Study Guide

The temperature at which a liquid changes to a gas is called the boiling point. At this specific temperature, the vapor pressure of the liquid equals the atmospheric pressure surrounding it, allowing the liquid to transition into the gas phase.

This process occurs when a sufficient amount of thermal energy is added to the liquid, enabling the molecules to overcome intermolecular forces that keep them in liquid state. When a liquid reaches its boiling point, it undergoes a phase change, which is typically accompanied by the formation of bubbles within the liquid. Boiling points can vary based on pressure; for instance, at higher altitudes where atmospheric pressure is lower, liquids boil at lower temperatures.

Understanding the characteristics of different phase changes is essential in physics as it relates to concepts of heat, energy transfer, and states of matter.