That bird toy...

Today, the blog post is inspired by a toy that I imagine many people would have played with in the past and looked fascinating as to how it worked. So I did a little digging to find out the physics behind the "magic" balancing bird.

This little toy has its centre of gravity located at the tip of its beak (where we set it to balance) due to the wings, which are angled forward, having enough mass to balance the mass at the tail. This allows the mass of the bird to be perfectly balanced on top of wherever it is resting, so the bird is in equilibrium. However, the physics doesn't end there.
There are two types of equilibrium: Stable and unstable. Unstable equilibrium is when the object causes high potential energy, so when a little force is applied, it can cause further displacement. Unstable equilibrium is caused when the COG is above the pivot. However, when the COG is below the pivot point, this will induce a stable equilibrium that this means that it will take much more force in order to displace the object. This balancing bird is designed to have a COG below the pivot, which is the finger or point you balance it on. This is done by angling the wings and the tail down below the pivot so that the bird is much more stable when balanced.

Like so:



Well, there you have it. The balancing bird explained!