Why is glacier ice blue?
Glacial ice is a different color from regular ice. It is so blue because the dense ice of the glacier absorbs every other color of the spectrum except blue - so blue is what we see!
It's Not Just Frozen Water!
Sometimes the glacial ice appears almost turquoise. Its crystalline structure strongly scatters blue light. The ice on a glacier has been there for a really long time and has been compacted down so that its structure is pretty different from the ice you normally see. Glacial ice is a lot different from the frozen water you get out of the freezer.
It's Not Just Frozen Snow!
Glacial ice is not just frozen compacted snow. There are other things in the ice that make it much different from the ice in your home. Glaciers move through rock and soil as they carve their way down a slope. This means the ice is going to have a lot more ingredients than just water.
Wow! Just Imagine...
What would happen if you broke off a big chunk of ice from a glacier and put it in your glass of water? Would it be any different from the ice in your freezer at home? What would happen to all those air bubbles that have been trapped under pressure?
- If your chunk of glacial ice melted in your glass of water, you would have dirt, gravel, and even organic matter [living stuff] in your water.
- All those pressurized air bubbles would rush out so fast that they might explode your glass!
Why is Glacier Ice Blue?
(some of the answers may come from the vocabulary list)
- Glacier ice is so blue because the dense ice of a glacier absorbs/reflects (circle one) every other color of the spectrum except blue/yellow (circle one).
- Glacial ice is different than regular ice. True or False?
- Are there rocks in glacial ice? Why or Why not?
- What could happen to your glass of water if you dumped glacial ice in it?
- What is the stuff called that is either alive now or was alive in the past (it may be trapped in glacier ice)?
- True or False: Glacial ice is just like the water in your freezer.
- What would be in your glass of water if the glacial ice melted?
- Glaciers are just frozen compacted snow. True or False?
- The ice on a glacier has been there for a long time and has been compacted down. True or False?
- If all the glaciers in the world melted, what would happen? (Use your imagination!)
Exercise: Blue Ice
1. Glacier ice is blue because:
- Its structure strongly scatters or reflects blue light
- It is lonely
- It absorbs every other color in the spectrum except blue
- Yellow and green make blue
2. Think about it:
How is glacier ice different from the ice in your freezer?
Project: Bubbles in an Ice Cube
Glacier ice is highly pressurized. Bubbles in glacier ice get squeezed and pushed around. Sometimes you can see round bubbles that have been squeezed into long rods or flat plains. Coarse-bubbly ice looks whiter than most other ice because it is filled with small bubbles. This kind is usually found near ablation areas of a glacier. Coarse-clear ice is free of bubbles and is the bluest ice of all. This kind is usually found near the margins and terminus of a glacier.
Look at ice cubes formed in your freezer. These ice cubes first froze on their outsides and trapped air bubbles toward the center. As a result, the exterior is bubble-free while the interior has bubbles. Bubbles between the outside and the inside of the cube are probably longer and more extended. Can you see the differences?
(Courtesy Glaciers of North America, By S. Ferguson)