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Aerodynamics
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Materials

      Candle.
      Ribbon glue.
      Paper.
      Matches.
      Hair dryer.
 

 
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Procedure

     1. Cut the paper leaf in two parts.

     2. Fold the papers parts in half and with ribbon glue link the opposite tips of each one. Air should not be allowed to get into the paper structure.

     3. Place a glass inside the paper structure. In this way you will have an oval paper structure to study the properties of air dynamics.

     4. Light the candle with matches and place it behind the paper structure.

     5. Place the paper structure in a way that the fold borders are vertical in comparison to the candle. (the candle should stay in the middle of the paper)

     6. Place the hair dryer in the opposite side of the candle and turn it on.

     7. Rotate the paper structure slowly in a way that the fold tips are turning for the air flow. (in the rotation movement end you will verify that the candle fire will turn off due to the stronger air flow in its direction)
 
Why?

  To minimize the attrition imposed to air flow in a object surface, several forms called aerodynamic have been developed. This modern object design implies a minimum resistance to air flow turbulence in its surfaces.
In the present experiment the initial paper form imposes a more turbulent air flow, making it impossible to turn off the candle flame. As you change the paper disposition, the air flow becomes more and more stronger to the candle flame. This is due to the fact that the final paper disposition offers less resistance to air flow (object more aerodynamic). In the end of the paper rotation it is acquired the best aerodynamic form, turning off the candle flamee. Now you know why modern cars have round fronts with a narrower surface.




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