Thermal expansion is the tendency of matter to change its shape, area, volume, and density in response to a change in temperature, usually not including phase transitions. When a substance is heated, its molecules begin to vibrate and move more, usually creating more distance between themselves, leading to an increase in volume. This phenomenon is observed in various materials, and it is an important property to consider when using materials at high temperatures
. In the context of the Earth's oceans, thermal expansion contributes to an increase in global sea level as ocean temperatures rise and water expands due to the absorption of heat
