Why Does a Weeble Never Fall Over? While a square brick is quite sturdy, stacking several bricks into a tall pile can easily lead to a topple. A water jug that is only half full stands very steadily, but if it is either empty or completely full, it becomes quite prone to tipping over.
Explaining Why a Weeble Never Falls Over
These two examples illustrate that for an object to stand firmly and not easily topple, it must meet two conditions: First, its base area must be large; second, its weight must be concentrated at the bottom, with a low center of gravity. The center of gravity of an object must be the point of application of gravitational force.
For any object, the larger its base area and the lower its center of gravity, the more stable and less likely it is to tip over. For example, structures that are shaped like towers always have a broad base and a pointed top. Similarly, when transporting goods, heavier items should be placed at the bottom and lighter ones on top.
A Weeble is a classic example of an object built according to this principle. The entire body of the Weeble is very light, with only the lower part containing a relatively heavy piece of lead or iron, resulting in a low center of gravity. Additionally, the bottom of the Weeble is wide and rounded, making it easy to wobble. When the Weeble leans to one side, the fulcrum (the point of contact between the Weeble and the surface) shifts, causing the center of gravity and the fulcrum to no longer align in a straight line. Under the influence of gravity, the Weeble will wobble around the fulcrum until it returns to its upright position. The greater the angle of tilt, the more pronounced the wobble caused by gravity, making the tendency to return to its original position even clearer, which is why a Weeble never falls over.
Similar to a Weeble, static objects that experience minor disturbances can regain their original equilibrium state, a concept known in physics as stable equilibrium. On the other hand, spherical objects like table tennis balls, soccer balls, or volleyballs can maintain balance at any position after being subjected to external forces. This state is referred to as equilibrium at all positions. Objects that can balance at all positions have their center of gravity and fulcrum aligned along the same vertical line, with the height of the center of gravity remaining unchanged. A pen resting horizontally on a table is an example of equilibrium at all positions; no matter how it rolls, the height of the center of gravity never changes.
