Why are blue icebergs blue?
Blue icebergs are a fascinating sight, breaking off from glaciers and melting in the ocean. They are a breathtaking example of the natural wonders of the world. But have you ever wondered why they’re blue? Let’s dive into the science behind the phenomenon.
What makes the ice blue?
As it turns out, the red part of light is absorbed by the ice, while the blue part is transmitted and scattered. This is a result of the way ice crystals refract (or bend) light, causing the shorter wavelengths to be scattered more than the longer wavelengths.
| Wavelengths of Light | Wavelength | Corresponding Color |
|---|---|---|
| 620-750 nanometers | Red | |
| 520-620 nanometers | Orange | |
| 450-520 nanometers | Yellow | |
| 400-450 nanometers | Green | |
| 380-400 nanometers | Blue | |
| 300-380 nanometers | Violet |
You can see that shorter wavelengths of light are scattered more than the longer wavelengths, which results in the blue color that we see. This principle is known as Tyndall scattering, and it’s responsible for many of the natural blue or blue-green colors we observe in the world, like the sky or the blue color of many minerals and rocks.
Why can’t we see the shorter wavelengths?
So why don’t we see more of the shorter wavelengths that are being scattered? Unfortunately, most of that light is absorbed by impurities in the ice or other materials that it’s passing through. This limits the amount of blue light that reaches our eyes.
Other Factors that affect the Color
• Impurities: Any impurities present in the ice will absorb or scatter light and affect the color.
• Depth of the Light: The longer the distance that light has to travel through the ice, the more it’s scattered. This is why deeper-blue icebergs are not as common as those that are closer to the surface.
Why is the ocean water blue too?
You might notice that when you look at an icebreaker ship cutting through iceberg-filled waters, the seawater around it often takes on a bluish tinge. This too is due to Tyndall scattering, but in a slightly different way.
Scattering in Sea Water
When sunlight penetrates the water, some of it is absorbed and some is scattered by impurities and other particles suspended in the water. Like with ice, this scattering favors the shorter blue wavelengths, making the sea water appear blue.
Now, let’s summarize!
Key Takeaways:
• Blue icebergs are blue because they absorb longer wavelengths of light and scatter shorter wavelengths (like blue and violet), which is a result of the way light interacts with ice crystals.
• Many other factors, like impurities and depth of the light, can affect the color of icebergs.
• Tyndall scattering is the principle that explains why the ocean and icebergs often have a blue or blue-green color.
There you have it! Next time you see a majestic blue icebreaker ship navigating through towering icebergs, just remember the science behind what makes them look so magical.