======Ball and Ring Expansion======


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**Alternative titles:** Thermal Expansion of Metals
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====Summary====                   
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====Procedure====  
  - Begin with the ball and ring apparatus at room temperature; pass the ball through the ring to show it fits.
  - Heat the metal ball evenly with a Bunsen burner while rotating it for a few seconds.
  - Attempt to pass the heated ball through the ring; it will no longer fit because of expansion.
  - Cool the ball by placing it in a beaker of water.
  - After cooling, try passing the ball through the ring again; it will now fit.



====Links==== 
Heat - Ball and Ring - Ong SK 1984: 
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Ball and ring expansion experiment - Chemistry with Mrs V: 
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📄 Ball and ring experiment - Sage: [[https://study.sagepub.com/chamberssouter3e/student-resources/chapter-8-types-of-matter/ball-and-ring-experiment]]\\


====Variations====
  *None




====Safety Precautions====
  * Safety glasses required when working with open flames.
  * Be cautious of hot metal and boiling water when cooling the ball.




====Questions to Consider====
  * Why does the ball no longer fit through the ring when heated? (Because metals expand when heated due to increased particle motion.)
  * Why does cooling the ball allow it to fit again? (Cooling reduces particle motion, causing contraction.)
  * What real-world examples use thermal expansion? (Expansion joints in bridges, bimetallic strips in thermostats.)