3. Humidity of Air
The amount of water vapours present in air is represented by a term called humidity. When the amount of water vapours present in the air is small, the air appears to be 'dry' and we say that the humidity is low.On the other hand, when the amount of water vapours in the air is large, the air appears to be 'damp' and we say that the humidity is high. So, humidity of air tells us the degree of 'dampness' of air.
When the humidity of air is low, then the rate of evaporation is high, and water evaporates more readily. Under these conditions, sweat from our body evaporates readily and we feel cool and comfortable.The wet clothes dry quickly under the conditions of low humidity of air. When the humidity of air is high, then the rate of evaporation is low, and water evaporates very slowly. In the later part of summer,the humidity of air increases. People sweat a lot in such weather. But the sweat from our bodies does not evaporate readily due to high humidity of air. Such weather becomes muggy (damp) and we feel hot and uncomfortable. This type of weather is experienced during cloudy days in the rainy season and in areas close to the sea (coastal areas). The wet clothes take a long time to dry when the humidity of air is high.
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3. 2. Liquid to Gas Change : Boiling (or Vaporisation)
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4. 2. Latent Heat of Vaporisation (Liquid to Gas Change)
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5. Classification Of Matter As Solids, Liquids And Gases
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6. Effect of 'Heating' and 'Cooling' on a Saturated Solution
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9. Why Solids, Liquids and Gases Have Different Properties
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14. 2. The Particles of Matter have Spaces Between Them
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15. 1. Solid to Liquid Change : Melting
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16. 3. Gas to Liquid Change : Condensation
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20. 1. Latent Heat of Fusion (Solid to Liquid Change)
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24. 1. The Particles of Matter are Very, Very Small
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26. 4. The Particles of Matter Attract Each Other
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28. 3. The Particles of Matter are Constantly Moving
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29. Characteristics of Particles of Matter
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30. 4. Liquid to Solid Change : Freezing
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31. Two More States of Matter : Plasma and Bose-Einstein Condensate
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38. The Common Unit Of Temperature and Si Unit Of Temperatre
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39. To Show That Solids and Liquids Cannot be Compressed but Gases Can be Compressed Easily
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44. To Show that Liquids do not have a Fixed Shape but they have a Fixed Volume
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45. To Show the Presence of Water Vapour in Air
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49. Gases Can be Liquefied by Applying Pressure and Lowering Temperature
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50. To Show that Gases do not have a Fixed Shape or a Fixed Volume
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