Magdeburg Plates
012–07190B
14
Activity 1
Sample data:
outside diameter of the large O-ring = 9.5 cm
inside diameter of the large O-ring = 8.5 cm
average of inside and outside diameter = 9.0 cm
Net Force = (atmospheric pressure - pressure inside the chamber) *
π
* (9.0 cm/2)
2
Net Force = (101 KPa - 5 KPa) *
π
* (9.0 cm/2)
2
Net Force = (96 KPa) *
3.14
* (9.0 cm/2)
2
(1 Pascal = 1 N/m
2
, and cm is meters x 10
-2
)
Net Force = (96 x 10
3
N/m
2
) *
3.14
* (9.0 m x 10
-2
/2)
2
Net Force = 610 N (approximately 137 lb or the weight of a 62 kg object)
(1 lb is approximately equal to 4.45 N; 1 kg is approximately 9.8 N)
Net Force = 137 pounds
Calculation with the small O-ring
outside diameter of the small O-ring = 6.0 cm
inside diameter of the small O-ring = 5.0 cm
Using the procedures and assumptions from the above example
Net Force = (96 x 10
3
N/m
2
) *
3.14
* (5.5 cm x 10
-2
/2)
2
Net Force = 228 N (approximately 51 lb or the weight of a 23 kg object)
Teacher’s
Notes
