092 – Balancing bird

Where does the center of gravity lie?  

Introduction to:  

Center of gravity, equilibrium of forces, stable equilibrium, mass distribution. 

Material:  

Balancing bird (made of hard plastic), available as a ready-made product.  

Instructions:  

• Place the bird on a finger with the tip of its beak.  
• Let the bird sway on the finger.  
• Make the bird turn slowly. 

Observation:  

Neither while swaying nor while spinning does the bird fall off the finger, its position is stable.  

Explanation:

• There are weights hidden in the downward curved wing tips, so the bird’s center of gravity is well below the tip of its beak.   
• The point of contact on the finger is therefore above the center of gravity. Thus, a stable equilibrium is maintained.