The Pendulum and the Winch

I often find that explaining computer science to non-computer-scientists is difficult.  It's been said that computer science is like no other field of study.  Well, I think that's a rather strong claim to make.  What follows is a translation of a standard problem in computer science into physics.  It is an analogy, unrealistic but nevertheless interesting.

I have a pendulum, supported by some apparatus ultimately connected to a pillar or pole.  It is possible to move the apparatus up or down, but only by manually detaching and reattaching it by hand.  I have a winch affixed to this apparatus which may raise or lower the pendulum.  It is connected to a coil of rope or string (which, for the purposes of this problem, is infinitely long yet magically takes up a finite volume), and can be remotely controlled at the press of a button.  The winch is also geared discretely; it only turns in units, and then only one at a time.

I wish to carry out a series of experiments involving varying the length of my pendulum.  In particular, I often want to lengthen the pendulum.  Most of the time, this setup suits me quite well.  But sometimes, I find I need a pendulum longer than the apparatus is high off the ground.  In these situations, I need to climb the pillar and move the winch up.  In so doing, I may need to start an entire experiment over again because the pendulum lost energy while I was climbing.  How can I avoid or minimize those climbs in proportion to the maximum length of the pendulum?  We must assume I do not know the maximum length in advance, perhaps because my experiments are highly complex and difficult to predict, or perhaps because they are directed by someone else's instructions, and they did not think to tell me in advance how long a pendulum I would need.

"Studies have shown..."

We've all been told that "studies have shown" something at one time or another.  Sometimes, our interlocutor is kind enough to give us a citation (and sometimes they aren't).  Well, let's do a thought experiment (if you're already familiar with significance testing, feel free to skim the next paragraph).

Suppose you give 20 labs a drug and a placebo, and tell them to test one against the other in clinical trials.  But instead of actually giving them a drug and a placebo, you give them two identical placebos (originally, I was going to use a homeopathic remedy vs. a placebo, but I didn't want to get sidetracked).  Assume the labs all use large sample sizes, statistical normalization, double blinding, and various other best practices.  None of them make any mistakes (or outright fraud, for that matter) and they all conduct proper, well-designed experiments.  Even under these ideal conditions, one of those labs (on average, and for pedants, we're assuming they all use α=5%) will tell you there's a statistically significant difference between the placebo and itself.