PADI Open Water Diver Practice Exam 2025 – Complete Prep Guide

Water density is influenced significantly by temperature. As water cools, its molecules move closer together, resulting in increased density. This is particularly true as water approaches the temperature of 4 degrees Celsius, where it reaches its maximum density. Below this temperature, water begins to expand as it freezes, leading to reduced density in ice compared to liquid water. Therefore, when discussing temperature changes, colder water is always denser than warmer water under normal conditions.

Warmer water, with its molecules moving more rapidly, tends to spread apart, making it less dense. This principle is essential for understanding buoyancy, thermoclines, and how temperature stratification occurs in aquatic environments. The idea that temperature does not affect water density or that water density remains equal at all temperatures contradicts the fundamental principles of physics and the behavior of water. Thus, the observation that colder water is denser than warmer water is consistent with established scientific knowledge regarding the properties of liquids.