Why do two ice blocks join to form one block when pressed together?a)T...
When two ice cubes are pressed together, the surface pressure temporarily decreases the melting point of the top layer of ice. This top layer melts and as soon as the pressure is released, the molten ice (water) freezes back into ice due to the low temperature of surrounding molecules and this effectively forms a kind of water weld between the ice cubes.
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Why do two ice blocks join to form one block when pressed together?a)T...
Why do two ice blocks join to form one block when pressed together?
Explanation:
When two ice blocks are pressed together, they join to form one block due to a phenomenon called regelation. Regelation is the process by which ice melts under pressure and refreezes when the pressure is released.
Key points:
- Pressure and melting point: The melting point of ice is lowered with an increase in pressure.
- Regelation: The process of ice melting under pressure and refreezing when the pressure is released.
- Joining of ice blocks: When two ice blocks are pressed together, the pressure at the point of contact increases. This increased pressure causes the melting point of the ice to decrease, allowing the ice to melt.
- Formation of a single block: As the ice melts at the point of contact, some of the water molecules from both blocks mix together. When the pressure is released, the water molecules refreeze, resulting in the two ice blocks joining to form one solid block.
- Regelation and glaciers: Regelation is also responsible for the movement of glaciers. The immense weight of the ice causes it to melt under pressure at the base, allowing the glacier to slide over the underlying surface. When the pressure is released, the water refreezes, anchoring the glacier in place until the next movement occurs.
Conclusion:
When two ice blocks are pressed together, the pressure at the point of contact causes the ice to melt. This melting allows the water molecules to mix, and when the pressure is released, the water refreezes, resulting in the two ice blocks joining to form one block. This phenomenon is known as regelation and is due to the lowering of the melting point of ice under pressure.
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