I'm working on a physics post, but it's a monster so it'll take a while.
In the meantime, here's some fun anecdotes from my many varied experiences working with many groups of children. You start to see patterns, you see. My job is to recognize the scared from the merely quiet and the safety-rule breakers from the merely loud ones, and engage everyone accordingly.
Some Kid Archetypes:
Know It All Kid. This kid, as I've encountered him, has been exclusively male. He claims to know all sorts of things about rock climbing or high ropes course, by virtue of having done it maybe once before in his life or of some other obscure thing like "climbing hay bales"--and is going to make a comment on everything you do. He's going to want to do it himself, is often not going to trust YOU to do it, and furthermore is going to push every single boundary of safety that you set just because he "knows it already" and the rules don't apply to someone who already knows. The one I've dealt with recently combined Know It All with Doesn't Actually Know Anything, so that he'd try to tie his own knot or clip himself in without actually knowing how, we'd correct him and he would claim that "no, I've got it!" and physically resist any attempts at correcting him, and we'd have to pull out our extreme sternness and generally watch him like a hawk to make sure he didn't do something ridiculous like untie himself halfway up the climbing tower.
Know It All Kid is a close cousin of Annoying Question Kid. Annoying Question Kid is also pretty much exclusively male, is usually prepubescent (because having a high pitched voice increases the annoying factor, unfortunately), and generally likes to glue himself to female instructors and, you guessed, Ask.Annoying.Questions. "What's this rope for?" "What do we have for lunch?" "What do you do that for?" "When do is it my turn?" "What does that thing do?", etc. Not that asking some of those things are bad, but Annoying Question Kid is usually so busy asking questions that he can't focus on what you are telling him to do vis a vis safety. He walks under ropes even after we've told him not to a handful of times, he runs up to climb without a helmet or even tying himself in...he's just in his own little world.
The I'm Way Too Cool For This Kid comes in both male and female varieties, usually more male in middle school than female, and often encompassing a large swath of high-school-aged participants. Personally, I can handle me some I'm Way Too Cool For This Kids, because they're not, and I have no problem goading them despite being Automatically Sooo Uncool for trying. A whole batch of them does make the day more frustrating, though. Note: there is also sometimes a Smart Ass Kid, who usually makes "haha, gay" jokes about everything you say, and he is usually very much in this category.
There is fairly often an I Hate Nature Girl, who spends pretty much the entire time decrying about how she is sooo not a nature person. Sometimes she is the same person as Scream At Every Little Thing Girl, who, when I'm trying to distinguish between genuinely-freaking-out verses just screaming because that's what girls are supposed to do, right? (giggle) really really gets on my nerves.
I've dealt with Excuses Kid of both genders, who, rather than, you know, being afraid, or having difficulty climbing something that is difficult, just has a rock in his or her shoe, or forgot to drink some water before climbing, or didn't sleep well last night, or suddenly has a cramp or a stomachache, or, oh, well, helmet's too loose, shoes are too big, etc. It's always a reason to just come down, and maybe try later, only when trying later, now has another weird cramp, or just remembered that he or she has a cut on his or her hand and shouldn't use it, or...you know.
There are Ultraquiet Ones who just don't say much, even when you are belaying them and they just stop somewhere and you try to ask them what is going on. They don't communicate what the problem is, they don't communicate what they want, they just sit there waiting for input from others. Since extremely freaked out people can go quiet like this, these kids are tough because it is hard to determine if and when they really need rescue.
Then there are the Adults, who are even worse at pushing themselves past things that challenge them than kids, whose teamwork is often marred by long-set behavior patterns they have the utmost difficulty noticing and changing, and who are appalingly bad about thinking that safety rules don't apply to them.