Tick – Tock

Got off on a mental side trip this morning

I have been doing some repair / time tuning on a long case pendulum clock (a.k.a. grandfather’s clock) in my home. I know the swing period of the pendulum is what regulates the accuracy of the time keeping.

Lengthen the pendulum which slows the period of oscillation and the clock runs slower. Shorten length for faster timing (which should be obvious.)

I started timing the “ticks” with the seconds displayed on my smartphone digital clock. I assumed the ticks should be related to the seconds ticking by. But this is not exactly the case!

The ticks were close to one second. But close doesn’t count for accurate time keeping. Or so I assumed.

This opened a door to a whole new world of discovery of pendulum clockworks and time keeping. I used the internet to broaden my knowledge of this subject.

Far too complex and interesting to explain here. I suggest you explore here for a start; https://en.wikipedia.org/wiki/Pendulum. Then follow the many links from there.

I see why some people become fascinated by clockworks and accurate time keeping with mechanical clock works dependent on earth’s gravity. There is a culture or society of people interested and fascinated with mechanical clocks. I could easily be there if I desired to spend the time and effort.

Electronic clocks have eliminated the variables of mechanical mechanisms and the physics of the earth’s environment. But it is these variables that make the subject so fascinating and complex.

Clock pendulums do have standard lengths for the number of beats per hour. Length is super critical while amount of weight has little to almost no effect. It’s not as simple as that. Mass does vary the length of the swing but not the period. Where the weight is located along the length is critical for timing.

Better minds than mine have been studying the variables of the pendulum clock since the dawn of the 1600’s.

There are many other effects associated with the mechanical motion of clocks. I have seen mechanical metronomes (a type of pendulum clock) sync to each other in “ticks” when set on a common surface. The slight vibrations push them into a common oscillation called injection locking. 

This may be ancient science today but that doesn’t make it less fascinating for understanding the physics of the natural world. I love these little “side trips” of discovery.