======Mass of Air======


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**Alternative titles:** Balloon Balance Experiment, Mass of Air in Balloon
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====Summary====                   
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====Procedure====  
  - Cut a piece of string about 1–2 feet long and tie it into a loop.  
  - Find the midpoint of a yardstick and loop the string around it, tying the other end to the roof or a stand.  
  - Clip two inflated balloons of equal size to the ends of the yardstick with binder clips. Adjust until the stick balances horizontally.  
  - Let the air out of one balloon by pricking the very top of it.  Do not burst it as pieces of balloon may be lost, affecting the weight.   
  - Observe that the side with the inflated balloon tilts downward, showing that air has weight.
  - Alternatively, a balloon can be weighed on a precise scale both empty and full of air.



====Links==== 
Balancing Balloons - Air Has Weight - funsciencedemos: 
{{youtube>o5LT_wfI98w?}}\\

Mass & Change: Balloon with and without air - chemtaiji: 
https://www.youtube.com/watch?v=kriCueCtuf8\\

📄 Weighty Matters: The Air Around Us - Small Step For STEM: [[https://www.smallstepforstem.com/air-weight-experiment/]]\\



====Variations====
  * Try using different amounts of air in the balloon to see if the scale tips more strongly.   
  * Try with different sizes or types of balloons to test consistency.



====Safety Precautions====
  * Supervise children when using scissors or tying balloons.  
  * Do not overinflate balloons - they may pop suddenly.  
  * Keep popped balloon pieces away from small children (choking hazard).




====Questions to Consider====
  * Why does the inflated balloon weigh more than the empty balloon? 
  * How does this experiment show that air molecules have mass?  
  * Why does gravity affect air the same way it affects solid objects?  
  * If air has weight, why don’t we usually notice it pressing on us?  
  * How does the weight of air relate to atmospheric pressure?