That pendulum thingy is a swinging toy. Pun intended.
It is said that Galileo first observed and pondered pendulum action while in church.Someone had bumped the chandelier while lighting the candles. The light fixture swung from side to side in pendulum mode. Galileo, not paying attention to the church service began to wonder about the physics of the situation. He timed the period of swings by using his pulse as a measure.
Jean Foucalt, the old french physicist used a pendulum along with a flat plate inscibed with markings similar to a compass rose. He observed that the pendulum not only swung to and fro but also in a very slow, small, circle. That experiment became physical evidence that the earth is rotating.
Velkyn had told us that she is a geologist. SHe will be familiar with the pendulum device used by past geologists to discover oil deposits. Their pendulum device would have a longer interval time when over an oil cavity.
The period of oscillation is unaffected by the mass of the bob weight. Nor is it affected by the width of the arc that it swings through. The only variables that affect period time is the length of the string and the acceleration og gravity (g). The factor g is normally taken to be 32 when calculated with the imperial system. To find the period of oscillation we can use the following formula.............Two times pi times the square root of L diviided by g. L is the length of the pendulum string. You can see that if either L or g is changed, then the swing period will change. That is what makes that fascinating pendulum video work. QUite simply, the varying length of the strings cause the swing periods to be different. Thinking of it in a different but still valid way, the speed of the balls is different from each of its neighbors.
To be sure that Brusspup guy is clever and probably a knowledgeable physics practitioner.