Physics Dept. Demonstration Manual

DS10 - Balanced Wine

Objective:

To provide an example of the relationship between the center of gravity and stability of a balanced object.

 
Apparatus:  
  • wine bottle, filled with water (unfortunately)
  • board, about 7 cm wide, 30 cm long and 2 cm thick, with an oblong hole to fit the neck of a wine bottle, about 8 cm from one end. The opposite end is bevelled at a 45 angle.


Method:

Hold the board in one hand with the 45 bevelled end resting on a flat horizontal surface. Using your other hand slip the neck of the wine bottle into the hole near the top end of the board. Carefully release both the bottle and board. If balance has not been achieved move the neck one way or the other as appropriate to achieve balance. When the bottle is properly positioned the balance is quite stable and the system will return to balance after one gently tips the board a few degrees from the rest position.