Explain the following :
(a) Water pipes in colder countries often burst in winter.
(b) In winter, water tank (or ocean) starts freezing from the surface and not from the bottom.
(c) Fishes survive in ponds even when the atmospheric temperature is below 0∘C.
(d) A hollow glass sphere which floats with its entire volume submerged in water at 4∘C, sinks when water is heated above 4∘C.
(e) A glass bottle completely filled with water and tightly closed at room temperature, is likely to burst when kept in the freezer of a refrigerator.
Explain the following :
(a) Water pipes in colder countries often burst in winter.
(b) In winter, water tank (or ocean) starts freezing from the surface and not from the bottom.
(c) Fishes survive in ponds even when the atmospheric temperature is below 0∘C.
(d) A hollow glass sphere which floats with its entire volume submerged in water at 4∘C, sinks when water is heated above 4∘C.
(e) A glass bottle completely filled with water and tightly closed at room temperature, is likely to burst when kept in the freezer of a refrigerator.
(a) On winter nights, as the atmospheric temperature starts falling below 4°C, water in the pipe lines expand and exert a great pressure on the pipes, causing them to burst.
(b) In winters, when temperature falls, the surface of water in the tank contracts, becomes denser and sinks to the bottom. A circulation is thus set up until the entire water in the tank reaches its maximum density at 4°C. If the temperature falls further, then the top layer expands and remains on the top till it freezes. Thus, water in a tank starts freezing from the top and not from the bottom.
(c) The anomalous expansion of water helps preserve aquatic life during very cold weather. When temperature falls, the top layer of water in a pond contracts becomes denser and sinks to the bottom. A circulation is thus set up until water in the pond reaches its maximum density at 4°C. If the temperature falls further, then the top layer expands and remains on the top till it freezes. Thus, even though the upper layer are frozen, the water near the bottom is at 4°C and the fishes can survive in it easily.
(d) On heating water above 4°C, the density of water decreases. As a result, the upthrust acting due to water on hollow glass sphere also decreases, which causes it to sink.
(e) Inside the freezer, when the temperature of water falls below 4°C, the water in the bottle starts expanding. If the bottle is completely filled and tightly closed, there is no space for water to expand, and hence, the bottle may burst.
(a) On winter nights, as the atmospheric temperature starts falling below 4°C, water in the pipe lines expand and exert a great pressure on the pipes, causing them to burst.
(b) In winters, when temperature falls, the surface of water in the tank contracts, becomes denser and sinks to the bottom. A circulation is thus set up until the entire water in the tank reaches its maximum density at 4°C. If the temperature falls further, then the top layer expands and remains on the top till it freezes. Thus, water in a tank starts freezing from the top and not from the bottom.
(c) The anomalous expansion of water helps preserve aquatic life during very cold weather. When temperature falls, the top layer of water in a pond contracts becomes denser and sinks to the bottom. A circulation is thus set up until water in the pond reaches its maximum density at 4°C. If the temperature falls further, then the top layer expands and remains on the top till it freezes. Thus, even though the upper layer are frozen, the water near the bottom is at 4°C and the fishes can survive in it easily.
(d) On heating water above 4°C, the density of water decreases. As a result, the upthrust acting due to water on hollow glass sphere also decreases, which causes it to sink.
(e) Inside the freezer, when the temperature of water falls below 4°C, the water in the bottle starts expanding. If the bottle is completely filled and tightly closed, there is no space for water to expand, and hence, the bottle may burst.
