Read the passage and answer the questions based on it. You are required to select your answers based on the contents of the passage and opinion of the author only. For many years, ship captains navigating the waters of Antarctica have been intrigued by sightings of emerald icebergs. Scientists have now explained their mystery. There, icebergs are turned upside down. Icebergs are blocks of ice that have broken off huge slabs of frozen snow called ice shelves. Their green appearance results from seawater that has frozen at the bottom over hundreds of years. The frozen sea water has dissolved organic matter which gives it a yellow tone and the fresh water ‘ice shelf’ above has a blue tinge. When the iceberg turns upside down, it appears green through the visual mix of yellow with the blue from below.
When the iceberg turns upside down, it appears ________.
Green
Understanding Emerald Icebergs in Antarctica
The passage describes the fascinating phenomenon of emerald icebergs seen in the waters around Antarctica. It explains that these icebergs, which are large blocks of ice broken off from ice shelves, sometimes turn upside down. This action reveals the ice that was previously at the bottom.
Why Icebergs Appear Green
According to the author, the green appearance of these icebergs is due to a specific composition when they are inverted. The passage explains the layering and color components:
- The upper part, from the original ice shelf, is made of fresh water ice and has a blue tinge.
- The lower part, which freezes from seawater over time, contains dissolved organic matter. This organic matter gives the frozen seawater a yellow tone.
When the iceberg turns upside down, the part that was previously at the bottom (with the yellow tone) is now visible from above, mixing visually with the inherent blue tinge of the ice. The passage explicitly states that the green appearance results from "the visual mix of yellow with the blue from below."
Answering the Question: Appearance When Upside Down
The question asks how the iceberg appears when it turns upside down. The passage directly answers this:
"When the iceberg turns upside down, it appears green..."
Therefore, based on the information provided in the passage, the appearance of the iceberg when it is turned upside down is green, resulting from the combination of the yellow from the frozen seawater with organic matter and the blue from the fresh water ice.
Conclusion
Based on the passage, an iceberg in Antarctica appears green when it turns upside down because the yellow colour from frozen seawater containing organic matter mixes visually with the blue tinge of the freshwater ice.
Revision Table: Key Points about Emerald Icebergs
| Feature | Description (from passage) |
|---|---|
| What are they? | Icebergs turned upside down. |
| Origin of Iceberg | Blocks of ice broken off from ice shelves. |
| Location | Waters of Antarctica. |
| Cause of Green Color | Visual mix of yellow (from frozen seawater with organic matter) and blue (from freshwater ice). |
Additional Information: Iceberg Colours and Composition
While the passage focuses on emerald icebergs, icebergs can appear in various colours depending on their composition and how light interacts with them. Here's a little more context:
- Blue Icebergs: These form from compressed snow that has expelled all the air bubbles. The dense ice absorbs red light and reflects blue light, making it appear intensely blue.
- Black or Transparent Icebergs: These can form from refrozen meltwater or when ice contains a lot of debris like rock dust or volcanic ash. Ice without air bubbles appears transparent.
- Striped Icebergs: Layers of snow can accumulate different materials over time. For example, layers of ice formed from meltwater might freeze clear, while other layers contain trapped air bubbles or even debris, creating stripes of different colours and textures.
- Green Icebergs: As explained in the passage, these are often associated with marine ice (seawater frozen onto the bottom of ice shelves) that contains organic matter or algae.
The passage specifically explains the green colour observed in Antarctica as a mix of yellow from dissolved organic matter in frozen seawater and the blue from the freshwater ice. This explanation is specific to the context of the passage and the author's perspective.
Similar Questions
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What are icebergs?
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Nature now needs to be protected from man because _____________
Forests are being destroyed in order to ________
The evil effect of destroying Nature instead of using it is seen in _________
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Important Questions from Reading Comprehension
What is the meaning of ‘intrigued’?
What are ice shelves?
What are icebergs?
The use of science in its simple form has helped man to ____________
Nature now needs to be protected from man because _____________
