Okay, if you're not looking to waste your time, go back to forum list.

DS7 last night told me how to protect myself in a plane crash. He said as the plane is approaching the ground, walk out on the wing, and at the last second jump off. I tried to say that whether or not I was on the wing I would be falling with the same velocity as the plane and I couldn't just jump off, and if I did, I'd land just as hard, but I was foundering in my explanation. Ignoring the practicalities (of the ensuing explosion, the inability to walk on the wing of a falling plane, etc.), can some of you math/science types tell me why? Thanks.

Wow, that's an amazing thought process for DS7. Wouldn't it be awesome if some aerodynamics engineer posts that he actually had something to his idea.
Something to think of: If the plane would burst into flames on impact, your son would be right to propose that you could survive by jumping off the wing at the right moment. Theoretically, of course. What a little smarty!!!!!!!!

Incog

I'm not math and science-y, but I can take a crack at it.

DS7's plan won't work because you're moving at the same velocity as the plane when you jump. So unless you can jump in the opposite direction at the same speed the plane is going at when it's crashing, you're still hitting the ground HARD. Humans can't jump that well!

BTW, "Mythbusters" tried this, only with a falling elevator. (Same principles in action, though.) I think they found that jumping didn't even help with that, and the speed would be a lot slower because you wouldn't have time to reach maximum velocity, as you would presumably do with a plane.

Thanks for the responses.

He is a mythbusters fan. We'll have to look for that episode.

Yes, I saw that episode. I love mythbusters! We watch it together like most families watch Dancing with the stars!!
Take the burning flame plane scenario, though. Even if you couldn't manage to jump free from the plane, If you were on the edge of the wing, your body would be thrown upon impact, thereby, placing you away from the burning plane. So who has a better chance at survival. Joe sitting in the burning plane or Joe thrown from the wing upon impact?

I

I think it comes down to whether you want to be crunched and charcoal or just crunched. But I think you're probably equally dead either way.



<I'm not quite dead yet! Think I'll go for a walk...>

heee heee heeeee.

Maybe some exploration into the whole idea would be fun.
I did a google search on these three words 'jet ejection seat' and found some interesting things which would help illustrate even the impossibility of jumping.
This is one of the links that came up, and probably beyond the capability of all but a few 7 year olds, but something to dream about:
the math behind ejection seats

OHGrandma, thank you. This is perfect. Of course, I don't want to go too much into the I'm just out of luck scenario, as DS wants to ensure that I'm safe if I have to travel (but for the record, I would choose crunch over crunch and charcoal just in case the charcoal came first). And Dottie, I'm with you. When he was telling me this last night while he was in the bath (where most of the deep thoughts seem to come out), I was thinking, how do I get out on the wing? Exit row, maybe? LOL!

How about "More accidents happen in the bathroom than in a plane"?

Or would he then be worried that he was in danger and never bathe again?

LOL! I already tell him that as he jumps in and out of the tub, stands up, splashes down, etc., etc. Worse is the mess he makes when he decides to swim or create waves by sliding down the back of the tub.

Ah, tub-swimming! I remember it fondly.

I love you people, I mean it I really love you all. The extent to which we take these threads is so awesome. Everytime I log on I find something to smile about.

Thank you, dear internet, I shall never be bored again!!

I

Are the 2 mutually exclusive? LOL!!! We love mythbusters AND DWTS in our house. (and I bet others of you here do too - you just don't want to admit it!!!)

You know me--I hide nothing! I'm a huge fan of both.

Though I just didn't like the group last season. No old 80s star for me to root for, so I didn't watch that one at all.

I've barely missed a single show in the other seasons though!

Woo hoo Kriston!!!! I KNEW someone else had to be out there!! I haven't missed a single show myself!

I like that it's positive and it shows people taking a chance and learning a new skill.

I never liked the nastiness of American Idol, so I watched about 2 minutes of it to see what all the hype was about and never watched again. Too mean-spirited.

But the DWTS judges really want to help the dancers improve. I think it's a good lesson in taking risks and banning perfectionism.

Plus I like to laugh at the crap music choices.

I just found this thread and would like to add that we watch both shows in our home too.

Questions,
My DS loved to read �The Worst Case Scenario Handbook� when he was 7-8! I couldn�t find it just now in his room, but it gives very detailed instructions for best survival odds in various situations. Your DS would probably love it too.

Oooh! My DH would like that, I suspect. Though I've been recently accused of not being an optimist, DH is the real pessimist in our household. He'd love reading about how to survive doom and gloom!

<grin>

Thanks, delbows!

delbows, thanks, I'll take a look (to make sure it's not too scary, even though it gives solutions). DS's comment when I shared the asnwers here was "then, Mommy, you should travel with a parachute." Good advice. btw, he did see that episode of Mythbusters.

questions,

(I tried to PM this response to you, but I don't think it went through -- I did not know you had started a thread. Anyway, here is my answer from the PM. Incidentally, I'm pretty certain I'm right about this -- it's basically a college freshman physics problem. There are various ways to complicate the problem taking into account air resistance, forward motion of the plane, etc.: your son will still turn out to be correct, although, unless he is a super-human jumper, his plan will only lessen the damage a bit.)
---

Your son has an interesting question -- I had to think for a moment. I'd bet the kid ends up being a scientist or engineer!

His suggested action actually would help a little, if you jump at the right time.

One way to think about it is, say, the plane is falling down at 100mph. If your kid can jump upwards at 10 mph (relative to the plane of course), that means he will kill 10 mph of the 100 mph, and will therefore only be falling down at a speed of 90 mph. Still a bad situation, but not quite as bad.

Incidentally, this is the sort of question that occurs to me spontaneously -- I'm in an elevator, it jerks and I start getting nervous, I remind myself of all the modern fail-safe devices in elevators (they're very good), and then I start to think about what physics says I should do if the elevator were to fall.

Knowing how to ask good questions is a huge part of being good at science -- your son sounds as if he has the right kind of curiosity.

All the best,

Dave

Thanks. I ended up starting a thread b/c my son was very eager for the answer. I was trying to remember the formula for acceleration, but couldn't remember my one course of college physics. Hadn't even thought about the forward motion of the plane... And yes, he wants to be a scientist.

questions,

Yeah, I kind of thought he might! Make sure he keeps open the option of being an engineer -- most people with science degrees end up working in engineering. Of course, at his age, science and engineering probably seem to be sort of the same thing -- basically it's a difference in orientation: solving practical problems using science or advancing abstract science for its own sake. I myself have worked in both.

Your son's problem can be milked to understand quite a lot of different issues, by the way. The way I described it was from the "frame of reference" of the "stationary" earth. I think the reason a lot of us get it wrong (I started to disagree with your son -- and then realized the kid had it right and it was I who was confused) is that we tend to view it from the frame of reference of the falling plane. Do that very carefully, and you still get your son's answer. Don't do it carefully, which for some reason seems to be the natural inclination for most of us adults, including me, and you get the wrong answer.

Einstein, incidentally, had a great skill for asking just this kind of �na�ve� question that turns out not to be so na�ve after all, and thinking it through very clearly to its conclusion � doing this led to both his special theory of relativity and to his theory of gravitation (�general relativity�). Some time in the next few years, I think your son might find interesting Bondi�s �Relativity and Common Sense� which presents special relativity in just this way � no knowledge of algebra required, just a willingness to think through carefully what is happening. And I�m pretty certain your son will enjoy Gamow�s �Mr. Tompkins in Wonderland� (now expanded into �Mr. Tompkins in Paperback�); I would read one of the editions by Gamow, not the ones that have been �updated.� Both should be available through your public library or through interlibrary loan.

Incidentally, this way of thinking is not only very powerful in science and engineering but also in economics and finance; personally, I think it has some utility in dealing with issues in politics and religion, but that is a bit more controversial!

The real question is how to get all kids to start wondering about these sorts of deceptively �simple� questions. I think one of the reasons that so many kids can zoom through math and science through at least the middle school level, but then get stalled at advanced high school or college level, is that they learn how to follow the rules but never stop to wonder and ask �childish� (but not really childish!) questions. Beyond second-year college math and physics, there is almost none of the �just follow the rules� stuff and it�s almost all �think carefully about what�s really happening� stuff. In a sense, you need to be a child to handle advanced math and physics.

Anyway, I hope your son keeps bugging you and everyone else with these sorts of questions. Any advice on how to encourage other kids to do the same?

All the best,

Dave

Am I the only one who doesn't really want to know the answer here? When I was a weeun, I remember seeing the Road Runner step safely outside of a falling elevator the moment before it hit the ground (of course poor Wile E. didn't think to get out). This was a sort of comfort for me throughout life. I would get on an elevator and think, "well, there's always a chance of survival!"

There is a chance! Always a chance! People fall from great heights and survive. Don't despair.

And, the amazing thing is that "cartoon physics" *seems* to make sense, doesn't it? Me, I was into Superman et al., and I still find it disappointing to know why almost none of his super deeds would actually be feasible (even granting super-strength, etc.).

Some enterprising psych folks have actually done a lot of research as to how we naturally think about physical phenomena. Basically, our natural inclinations are almost always wrong. Even kids who got top grades in introductory physics classes tend to blow it on "simple" questions such as "questions'" son asked.

In a way, learning science is sort of mentally rebelling against natural human ways of thinking, which is why it is so important to ask the simple questions and not just think you have learned science if you can explain E = mc2.

But I'm still disappointed that Superman's feats are not really possible.

All the best,

Dave

Thanks, everyone, for your responses.

I actually found an ask a scientist site and emailed DS's statement yesterday. They wrote back and said that a person on the wing would still be moving with the same force as the plane, so no luck, and would be even worse off b/c there would be nothing to absorb some of the impact like the crumple zone in a car. And the parachute would force the person back into the tail.

PhysicistDave, the Tompkins books look interesting. I think DS would love them, and I agree about the not reading the modernized one, having looked at the first chapter excerpt on Amazon (e.g., why change a reference to all those celebrity "Hollywood romances" to all that "sex and violence" in the movies?...). My one question is whether the originals are outdated by more recent science. I also saw an older book on infinity by Gamow that people loved and "grew up on." Do you think it's outdated (although how could infinity be outdated)? Looking at the excerpts on Amazon, I think DS would love them. Infinity is one of his favorite things to think about. Well, that and Bionicles...