TIP OF THE ICEBERG
From above the water, some icebergs appear huge, but this is just a small part of them. About 90 per cent of the ice floats below the waterline. With only one-tenth of the iceberg’s mass above the surface, it might seem surprising that these frozen blocks don’t sink. This works because of the density difference between freshwater and saltwater. Seawater is more dense than the iceberg, so the ice rises to the surface. The hydrogen bonds of the ice are spaced farther apart than the molecules in water, so the mass of the iceberg will take up much more space than the equivalent mass of water. Icebergs are also filled with trapped air, adding buoyancy and whiteness.