A Hot Pendulum

If the length \(12.42\,cm\) prove to be to short for a sustained swing,

\(f_{res}=\cfrac{1}{2\pi}\sqrt{\cfrac{g}{4l}}=\cfrac{1}{2}*\cfrac{1}{2\pi}\sqrt{\cfrac{g}{l}}=\cfrac{\sqrt{2}}{2}\)

a length of \(4*l=49.68\,cm\) at half the required frequency might swing a bit longer.

Maybe...