Florida Biology EOC Practice Test

How does the density of frozen water compare to liquid water?

1. Frozen water is denser

2. Frozen water is less dense

3. Liquid water and frozen water have equal density

4. It varies depending on temperature

The correct answer is: Frozen water is less dense

Frozen water is less dense than liquid water. This unique property is primarily due to the molecular structure of water. When water freezes, the molecules arrange themselves into a crystalline structure that is held together by hydrogen bonds. This arrangement creates open spaces between the molecules, leading to a greater volume for the same mass compared to liquid water, where the molecules are more tightly packed. As a result, when ice forms from water, it expands and becomes less dense, which is why ice floats on water. This phenomenon plays a crucial role in aquatic ecosystems, as it insulates the water beneath, allowing life to thrive even in colder temperatures. Understanding this concept is essential in biology and chemistry, as it has implications for climate, marine life, and the behavior of substances in various states.