Stability demonstrator

An object topples over when its center of gravity (or center of mass) moves beyond its base of support. This process can be understood using concepts from physics, particularly equilibrium and stability.

Here’s how and why it happens:

### How it Happens:
1. **Center of Gravity (COG)**: Every object has a point where its mass is considered to be concentrated, known as the center of gravity. The position of the COG depends on the shape, size, and distribution of mass within the object.
  
2. **Base of Support**: This is the area enclosed by the points where the object touches the surface (e.g., the base of a box on a flat table). The object remains stable as long as its center of gravity is above its base of support.

3. **Torque and Tipping**: When an external force (like a push or a tilt) is applied to an object, it creates torque, or a rotational force, around a pivot point (often the edge of the base). If the applied torque causes the center of gravity to move beyond the edge of the base of support, the object will rotate and topple over. Gravity pulls downward on the center of gravity, and once it's no longer over the base, there's no opposing force to prevent it from falling.

Simply said: “Keep the center of gravity as low as possible”.

This model shows the difference between a high center of gravity or a low one.

The second model explains the principle when the vertical from the CoG leaves the base the object tips over.

To simulate the center of gravity I use a glass marble of 30 mm (approx. 32 g). The simulated CoG is not exactly in the middle of the red sphere, but accurate enough to demonstrate the principle. When you replace the glass marble with a steel ball (approx. 100 g) the accuracy will improve.

I printed all models with PLA, 0.2 mm layer, 15% Infill and supports. I blocked the supports for the 1.8 mm alignment holes. I added forced supports for the long struts. They are finicky and can easily break during printing. See the .3mf files.

After printing you have to glue the parts together. For alignment I created 1.8 mm holes where you can, at one side, put in short (max. 5 mm) pieces of filament. This makes aligning during glueing a breeze. Likely you have to ream those holes a bit with a 1.8 mm drill.
Also do not forget to put your steel or glass ball in before glueing!!