Sam's Odyssey 101

August 22, 2026

I have been playing with the recently bought mechanical watch movement toy almost every day. I decided to do a simple experiment with it.

As the mainspring unwinds, it moves the escapement and then the balance wheel, which oscillates. I wanted to test if the oscillation period of the balance wheel stays constant until the mainspring stops.

(Experiment)

I wound the mainspring and recorded the movement on video. I measured the time for 10 oscillations of the balance wheel at different times while the mainspring was unwinding. (10 oscillations instead of just one to make the timing error smaller.)

The period is T = (time for 10 oscillations) / 10.

My experimental variables are

• Independent variable: time after the movement started
• Dependent variable: oscillation period of the balance wheel (T)
• Controlled variables: same movement, same position, same recording condition

(Results)

The average oscillation period: T = 0.34 seconds. (Frequency = 1/T = 2.9 Hz)

I could also see that the maximum rotation of the balance wheel changed as the movement ran, although I could not measure the rotation angle well. Nevertheless, the oscillation period stayed almost the same (0.34 s). It is an impressive result for this toy movement.

(Conclusion)

Before doing this experiment, I had mostly watched the components because I thought the movement looked interesting. Measuring it made me realize again that the important thing is not just how the parts move, but “how they manage to keep time so consistently.” I still don’t understand that part well, but I am very curious.