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2B40.40 - Weight of Air

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​2B40.40 - Weight of Air

Preview
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Title2B40.40 - Weight of Air
Objective

Demonstrate that air has weight​

StatusAvailable
Assembly Instructions

 

Instructions:  The large brass sphere is filled with air and sealed.  The small brass sphere is solid.  The two spheres are balanced on an equal arm balance and placed inside the bell jar.  A camera is clamped to the vacuum pump apparatus so that the least number of reflections are seen in the picture.  If requested, include a small amount of putty to show amount needed to displace balance by same amount as when chamber is evacuated.​

 

Setup Time20
Operation Time10
Preview Time5
Operation Instructions

Instructions:  Place the equal arm balance inside the bell jar.  One of the spheres is full of air while the other sphere is solid.  The two spheres should be balanced when placed inside the bell jar.  When ready, begin to evacuate the chamber, and observe the arm of the balance start to tilt.  This tilt is due to the greater mass of the large sphere (air).  If desired, you can then vent the chamber and place a piece of putty onto the larger sphere to displace the balance by the same amount as when the chamber is under vacuum to give the students an idea of the weight of the air in the brass sphere. ​

ExportableNo
Demo on DimeNo
PIRA 200No
Export Instructions (if different)
HazardsNone
Analysis/Information
Category2 Fluid Mechanics
Subcategory2B - Statics of Fluids
KeywordsWeight of gas, air, vacuum
Construction Information
 
Equipment TitleUse SHIFT+ENTER to open the menu (new window).
  
QuantityUse SHIFT+ENTER to open the menu (new window).
  
vacuum pump - mounted on cart, with bell jar
1
two brass spheres on equal arm balance
1
camera - b&w
1
squeezee clamp
2
putty