AP BIOLOGY

Detailed explanation-1: -What’s so special about ice that causes it to float? Believe it or not, ice is actually about 9% less dense than water. Since the water is heavier, it displaces the lighter ice, causing the ice to float to the top.

Detailed explanation-2: -The extra hydrogen bonds that occur when water freezes increase the space between molecules, causing a decrease in overall density. In fact, each water ice molecule forms hydrogen bonds with four other molecules, while water molecules only form hydrogen bonds with an average of 3.4 other molecules.

Detailed explanation-3: -Solution: Density of ice is 0.9 g cm-³ whereas the density of water is 1 g cm-³. Since ice has less density than water, it floats on water.

Detailed explanation-4: -The “stuff” (molecules) in water is more tightly packed than in ice, so water has greater density than ice. Don’t let the fact that ice is a solid fool you! As water freezes it expands. So, ice has more volume (it takes up more space, but has less density) than water.