11, జులై 2016, సోమవారం
Relation between change in temperature and specific heat:
- The rate of increase and the rate of decrease in temperature of a substance depend upon the nature of the substance and specific heat of the substance.
- If the specific heat is high, the rate of rise or fall in temperature is low for same quantity of heat supplied.
- It gives us an idea of the degree of ‘reluctance’ of a substance to change its temperature.
- High specific heat substances increase their temperature slowly and decrease their temperature slowly.
Applications of Specific Heat capacity:
a) Reason for a water melon brought out from the refrigerator retains its coolness for a longer time:
1. Water melon contains a large percentage of water.
2. Water has greater specific heat. Therefore the rate of rise in temperature (decrease in temperature) is less.
3. So, the temperature of the water inside the water melon takes more time to increase.
4. Hence, water melon retains its coolness for a longer time.
b. Reason for a samosa appears to be cool outside but it is hot inside:
1. The inside substances of samosa have more specific heat.
2. So, it retains hotness for a longer time.
3. therefore, appears to be cool outside, but it is hot when we eat it.
c) Reason for Stabilizing atmospheric temperature during summer and winter seasons:
1. Due to high specific heat of the water, in summer season, day time temperature of sea water (ocean water) increases very slowly increases, where as the temperature of the earth rise rapidly.
2. Due to this reason, the air above the earth increases its temperature, expands and decreases density.
3. Therefore, cold ocean air flows towards the earth and cools down the atmospheric temperature on land
4. In winter season, night time the earth cools very fastly compared to ocean water by losses its heat.
5. Air above the hotter ocean water expands and decrease density.
6. As a result, hot air on the earth flows from the earth to oceans.
7. So, we appreciate the role of oceans in stabilizing the atmospheric temperature.
d) Role of oceans in stabilizing atmospheric temperature:
1. Heat energy transmits daily from sun to earth.
2. The oceans behaves like “heat store houses’ for the earth
3. They can absorb large amounts of heat at the equator without appreciable rise in temperature due to high specific heat of water.
4. Therefore, oceans moderate the surrounding temperature near the equator.
5. Ocean water transports the heat away from the equator to areas closer to the north and south poles to moderate the climates in parts of the earth that are far from the equator.
6. So that we appreciate the role of oceans in stabilizing atmospheric temperature.