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CONDUCTION! PowerPoint Presentation
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CONDUCTION!

CONDUCTION!

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CONDUCTION!

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  1. CONDUCTION!

  2. THE DEFINITION! :D Conduction is the transfer of thermal energy from a region of higher temperature to a region of lower temperature through direct molecular communication within a medium or between mediums in direct physical contact without a flow of the material medium. The transfer of energy could be primarily by elastic impact as in fluids or by as predominant in metals or phonon vibration as predominant in insulators. In other words, heat is transferred by conduction when adjacent atoms vibrate against one another, or as electrons move from atom to atom.

  3. SOLIDS! Wee! Conduction is greater in solids, where atoms are in constant contact. Metals (eg. copper) are usually the best conductors of thermal energy. This is due to the way that metals are chemically bonded: metallic bonds (as opposed to covalent or ionic bonds) have free-moving electrons and form a crystalline structure, greatly aiding in the transfer of thermal energy. HEAT HEAT HEAT HEAT HEAT HEAT [c] L.E.D.V

  4. LIQUID! Woo! Substances vary in their ability to transfer energy in this way. As we have just noted, metals are generally good conductors. Water is a bad conductor, as can be verified by trapping a piece of ice at the bottom of a test-tube of water and heating the top. The water at the top will boil without the ice melting. Fluids (except liquid metals and gasses) are not typically good conductors. This is due to the large distance between atoms in a gas: fewer collisions between atoms means less conduction. As density decreases so does conduction.

  5. GAS! Yeah! Conductivity of gases increases with temperature but only slightly with pressure near and above atmospheric. Conduction does not occur at all in a perfect vacuum.

  6. The transfer of heat by conduction and convection may be demonstrated with two similar balloons, one filled with air, the other with water. When a match is brought close to the air-filled balloon, the balloon ruptures. However, when a match is brought within the same distance of the water-filled balloon, the balloon remains in tact. Conduction and convection carry the heat away from the balloon before the temperature required for melting occurs.  A second reason the balloon doesn’t burst is related to the heat capacity of water. Water is able to absorb a great deal of heat with little change in temperature.

  7. EXAMPLES OF CONDUCTION IN DAILY LIFE (;

  8. SOLID:

  9. LIQUIDS: A spoon in a cup of hot soup becomes warmer because the heat from the soup is conducted along the spoon.

  10. GAS :

  11. QUESTION TIME >.< • What is conduction ? Answer: Conduction is the transfer of energy through a substance without any bodily movement of the substance.

  12. 2. Why is conduction greater in solids? Answer: In solid, atoms are in constant contact.

  13. 3.Why are fluids not typically good conductors? Answer: This is due to the large distance between atoms in a gas: fewer collisions between atoms means less conduction. As density decreases so does conduction.

  14. 4. A different example of conduction in daily life.

  15. CreditsY Li Xuan Dawn Vanessa Erysha Images : www.google.com Information : http://www.wikipedia.org/

  16. Thank You :x