Diffusion in Solids
Diffusion can also take place in solids. Diffusion in solids is a very, very slow process. We will now give two examples of diffusion of solids in solids.
(i) If we write something on a blackboard and leave it uncleaned for a considerable period of time (say, at least 10 to 15 days), we will find that it becomes quite difficult to clean the blackboard afterwards. This is due to the fact that some of the particles of chalk have diffused into the surface of blackboard.
(ii) If two metal blocks are bound together tightly and kept undisturbed for a few years, then the particles of one metal are found to have diffused into the other metal.
The diffusion of a solid substance into another solid substance is so slow that many people think that diffusion does not take place in solids at all. The diffusion in solids is very, very slow because the particles in solids do not move from their fixed positions. The particles of a solid only vibrate about their fixed positions. Due to lack of appreciable movements in the particles of solids, the diffusion of solids in solids is rare. Before we go further and discuss the units of temperature, please answer the following questions :
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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. Effect of 'Heating' and 'Cooling' on a Saturated Solution
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6. Classification Of Matter As Solids, Liquids And Gases
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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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