Explain how glaciers become blue
Glaciers appear blue because of the way that ice absorbs and scatters light. When sunlight shines on a glacier, most of the colors in the light spectrum are absorbed by the ice and then reemitted as blue light. This is because ice is made up of tightly packed molecules that absorb the longer wavelengths of light (such as red, orange, and yellow), while shorter wavelengths (such as blue) are scattered back out. This scattering effect makes the ice appear blue to our eyes.
Additionally, as glaciers become denser and thicker, more air bubbles are compressed out, which can also contribute to the bluish color. The lack of air bubbles means that there are fewer surfaces for light to reflect and scatter off of, which further enhances the blue appearance of the ice.
In summary, glaciers appear blue due to the way that light interacts with the densely packed ice molecules and the lack of air bubbles within the ice.