Why Are Icebergs Blue Underneath? The tip of an iceberg appears white while the bottom appears blue due to differences in how light interacts with the ice's structure. At the top, the ice contains many tiny air bubbles and cracks that scatter all wavelengths of visible light. This scattering is diffuse and non-selective, resulting in a white appearance, much like snow. In contrast, the bottom of the iceberg is older, denser ice that has undergone compression, squeezing out most of the air bubble