Book 19, Question 33
Why Are Some Rivers Milky Turquoise?
Some rivers are milky turquoise because glaciers grind rock into a fine powder! The powder is called rock flour. It floats in the water and scatters blue-green light.
More fun facts
- Milky turquoise rivers are often fed by glaciers.
- Glaciers grind rock into a fine powder called glacial flour.
- Meltwater carries the tiny rock bits into rivers and lakes.
- The tiny crystals float in the water and give it a milky blue-green color.
- Lake Pukaki in New Zealand is turquoise from glacier-fed rivers.
Sources: NASA Science, National Park Service
Questions kids ask
What is glacial flour?
It is fine rock powder ground up by glaciers. It floats in the water and gives it a milky blue-green color.