
Myth: The astronauts didn’t float away because they had heavy boots - andrelaszlo
http://blog.sciencegeekgirl.com/2009/11/09/myth-because-the-astronauts-had-heavy-boots/
======
steveridout
I think the people who answered wrongly aren't thinking in a first principles,
physics-based mindset, but just instead just recalling previous memories and
reasoning in an intuitive, fuzzy kind of pattern-matching.

We've all seen images of pens floating weightless in _space_ on films and TV,
and we probably haven't ever seen pens falling on the moon. But the moon is in
space right? so... yeah, why not, it floats.

And for the guys on the moon, well I haven't got any memories of astronauts
_without_ boots on, and those boots sure look big and heavy, they're special
_gravity boots_ , I'm sure I heard that on TV once, yeah, that's probably it.

The first principles approach of applying the concept of universal
gravitational attraction probably isn't even entering their heads, _even if
they 've been taught it_.

This used to get on my nerves, how can people be so stupid? Why won't they
just _think_ for a moment!? But recently I've been focussing some effort on
learning a language (Spanish) and realise that in that this case the first-
principles style of learning that works so well for physics and maths is
largely useless, and it's better to turn off the analytical side of your brain
and not think too much, just keep exposing yourself, trying to communicate,
and let your subconscious do it's stupid fuzzy pattern-matching, and it does a
remarkably good job!

~~~
cleaver
I grew up as a space junky, with NASA still running manned missions when I was
a kid. It didn't take me very long to understand the concepts of gravity on
the moon vs. earth. I trust that if I asked grade-school me, I'd get the right
answer.

While it didn't take long to get the physics of the problem, it took a lot
longer for me to grasp the social side of things. Specifically, if your grade
six teacher says something stupid like this, there is absolutely nothing to be
gained from correcting her. I wish I could go back in time and clue me in.

OTOH, if it's a university lab at a science and engineering school, then give
'em hell.

~~~
_Adam
You may not gain anything correcting your sixth grade teacher, but by not
correcting her, something can be lost. A world where teachers can spout
bullshit without any opposition is not one I want to live in. And given we
only have one world...

Perhaps it was irrelevant in your case. Or perhaps your skepticism inspired a
fellow student to become an engineer. Who knows?

------
gadders
At my daughter's school, they had an assembly for parents to attend that
celebrated, amongst other things, the first landing on the moon.

The children boldy proclaimed that the reason the hammer and the feather hit
the ground at the same time in the famous experiment was because there was
less gravity on the moon.

It still rankles with me a year later.

~~~
DanBC
That's a shame. Was there any opportunity to assess the material before it was
presented? Was there any method to correct mistakes after?

Your daughter presumably understands that it's not about gravity but air
resistance. Has she told all her pals? Because that kind of subversive
teaching could be really powerful. TEACHERS HATE HER; THE GRAVITY SECRET
_THEY_ DON'T WANT _YOU_ TO KNOW!!! etc.

May I ask, hold old was your daughter? What kind of science teaching should
she be getting? (Obviously, not anything that wrong).

~~~
gadders
She was 6 at the time. I told her afterwards it was wrong but I regret not
telling the teachers.

------
informatimago
I think the key is this sentence: "Many students thought the pen would float
away. One year, she asked them instead about a crescent wrench instead of the
“apocryphal pen.” They all answered that question correctly!"

People just DO NOT think.

Everybody has SEEN (on TV, where they spend more time in front of, than in
school or reading books) astronauts in orbit demonstrate they're weighless, by
showing a pen float in front of them.

So space = floating pens, in their visual memory.

Moon is in space, therefore pens float.

What about a wrench? Oops, no visual memory to answer, bummer, they'll have to
think! And of course, some of the little teaching they had pegged, and they
can answer correctly.

That's all. People DO NO think.

Why do you think, IBM had to put up "THINK!" panels in its offices?

~~~
dennisgorelik
> People just DO NOT think.

People think. They just generally do not think about Physics.

~~~
Double_Cast
I think he's referring to cached thoughts. Thinking critically takes more
effort than retrieving cached thoughts. So why think critically in lieu of a
ready made meme?

------
andyjohnson0
Site seems to be down. Cached version is here:
[http://webcache.googleusercontent.com/search?q=cache:uWHPLrG...](http://webcache.googleusercontent.com/search?q=cache:uWHPLrGJYW4J:blog.sciencegeekgirl.com/2009/11/09/myth-
because-the-astronauts-had-heavy-boots/)

A significant part of the article is a reposting of
[http://www.phys.ufl.edu/~det/phy2060/heavyboots.html](http://www.phys.ufl.edu/~det/phy2060/heavyboots.html)

Edit: Changed wording re how much of article is repost

~~~
masklinn
>Article is mainly just a reposting of
[http://www.phys.ufl.edu/~det/phy2060/heavyboots.html](http://www.phys.ufl.edu/~det/phy2060/heavyboots.html)
though...

That is an unfair characterisation, I think. The article does indeed reproduce
heavyboots in its 725 words entirety (according to pages's word count for what
that one's worth), but tacks a further 930 words afterwards. And these 930 are
interesting indeed as they're further explorations of the phenomenon and
discussion on its underlying reasons.

~~~
andyjohnson0
Fair enough - I've changed the wording a bit. Personally, though, I thought
that the follow-on discussion didn't add much beyond what was mentioned in the
original heavyboots article.

------
josephlord
From the comments:

> I answered gravity on a physics test in high school for the question “What
> force works at a distance” and got it wrong because the professor wanted
> electromagnetism. When I took the paper up to him to contest it, he told me
> that gravity doesn’t count because it only exists between planets. I got the
> physics book and ..."

I was sure at that point he was going to say "dropped it on the floor" but no
such luck.

> "...read to him out of it but he cut me off and claimed that what I had read
> proved his point."

------
DanBC
See also this website. They ask the question to students, and we know the
courses the students are taking.

[http://www.falstad.com/gravity.html](http://www.falstad.com/gravity.html)

> Physics 324 - Modern Physics for Engineers

> "A body is at rest tends to stay at rest, plus there's no gravity"

> "The gravity of the moon can be said to be negligible, and also the moon's a
> vacuum, there is no external force on the pen. Therefore it will float where
> it is."

> "The pen will float away because the gravitational pull of the moon, being
> approximately 1/6 that of the earth, will not be enough to cause the pen to
> fall nor remain stationary where it is. The gravatational pull of other
> objects would influence the pen"

It's a bit scary seeing what the answers are.

I guess we need to remember just how long ago it was that anyone was on the
moon, or any distance into space.

An ASCII diagram.

    
    
           e   g                          m
    
           earth geosynchronous           moon
    

Since 1980 we've sent people maybe a pixel from e.

~~~
christianmann
>> "The gravity of the moon can be said to be negligible, and also the moon's
a vacuum, there is no external force on the pen. Therefore it will float where
it is."

That one's almost correct; it's just an issue of scale; they don't realize how
big/heavy the moon actually is.

~~~
Crito
The issue is that they presumably understand that the moons gravity _isn 't_
negligible, since damn near everybody on earth has seen the Apollo 11 moon
landing videos. They are not merely missing information needed to answer the
question and making the wrong assumption. They have all of the necessary
information, but get it wrong anyway because for whatever reason, they aren't
_using_ all of the information they have.

~~~
DanBC
> since damn near everybody on earth has seen the Apollo 11 moon landing
> videos.

Is that true? I suspect it's true for people over 30 or who have special
interest in STEM, but not so true for anyone else.

~~~
Crito
I would say that the footage has been used enough in various forms of media to
have just about everyone covered. Stuff like this at least:
[https://www.youtube.com/watch?v=182oUgBfoLE](https://www.youtube.com/watch?v=182oUgBfoLE)

One way or another, I think everyone but very small children or reclusive
hermits have seen at least _some_ footage of an Apollo astronaut bouncing
around on the moon.

------
cynichacker
I would add another answer choice to the question 25:

25\. When the Apollo astronauts were on the Moon, they did not fall off
because: (f) They were on Earth

------
rz2k
I think a lot of people who are skeptical of this story just don't realize
that they appended to be surrounded by people who have developed unusually
accurate physical models.

I recommend browsing Amazon reviews of (non heat pump) electric heaters for
statements about which ones are more efficient. (The less efficient one
produce more waste heat?)

Because there are few consumer products that exercise people's understanding
of gravity, basic thermodynamics might be a good proxy. However the real point
of the article isn't all the misconceptions that must be "plucked out" one by
one, but the struggle of trying to figure out how to encourage students to
form more comprehensive models.

I'd also add that an important goal in teaching is students' facility in
applying principles, and confidence to question intuition and consensus.

~~~
jhonkola
Well, in case of electric heaters used to heat a home the efficiency should
really be measured in terms of "how much electricity is consumed if the heated
room is kept at constant 20C measured at e.g. center of room". This is
somewhat dependent on the quality of the thermostat controlling the heater.

Then, I think that there are some real differences found in the efficiency of
the heaters.

~~~
quasse
If you're still talking about electrical heaters here, there's literally no
where for the energy used to go other than into heat for the room.

If you have two 1000w heaters, one made from a potato and ten clothes hangers
and the other made from the highest quality materials known to man, they will
still both heat a room the same amount.

Granted, one might have a better fan or more airflow and might therefore
provide a more even heat distribution in the room, but they will both be
providing the same amount of heat to the interior of the room. That's just how
energy balances work. If 1000w is flowing from the plug into the heater and
it's not being stored anywhere in the heater itself there's nowhere for it to
go but into heat for the room.

------
onion2k
This _must_ be nonsense. Or an April Fools joke. Or something. I don't want it
to be true. It can't be.

 _sobs quietly_

~~~
cstross
Go forth and ask random people whether (a) the earth revolves around the sun,
or (b) the sun revolves around the earth.

The proportion giving answer (b) will cause you to sob even more.

(Yes, I have done this. Afterwards, I hid under my bed bewailing the ignorance
of my fellow hominids.)

~~~
spindritf
Both a and b are true (after you fill in the missing information). With two
objects it's only a matter of chosen frame (or point) of reference. I'd argue
that since you're on Earth, b makes more sense.

The importance of the heliocentric model comes from the fact that there are
more objects in the solar system. With multiple objects you could also hold
any one of them still but it makes the model much more complicated and the
attraction between the objects less intuitive.

~~~
ealloc
b is ruled out to a "reasonable" person because the Earth is not an inertial
reference frame, but is clearly the 'rotating' frame, while the Sun is
(approximately) stationary.

This is confirmed through the phenomena of stellar parallax and stellar
aberration, which are only visible from Earth because of its motion. Even back
in the 1573, Thomas Digges and many successors realized they could prove the
Earth was in motion using parallax (though had trouble detecting it), and in
1729 James Bradley gave the first proof of heliocentrism using aberration.
Both of these observations were taken as proof by the scientific world that
the Earth orbits the Sun, and not the other way around.

------
leoc
The heavy-boots answer seems pretty justifiable in the case where you have a
correct intuition about how gravity itself works but simply underestimate how
strong the Moon's gravity happens to be. Set the parameters just-so and there
_would_ be a threshold effect, as on an asteroid massive enough to walk on but
not-massive enough to jump off.

~~~
jere
Exactly! This reminded me of the Little Planet what if [http://what-
if.xkcd.com/68/](http://what-if.xkcd.com/68/) Munroe claims on a small, super
massive planet, you could overcome escape velocity with a sprint. It doesn't
work the same on the moon obviously, but only because the moon has significant
gravity.

>Which, pointed out a discussant, suggests that students are using buoyancy as
an analogy — if you’re heavy enough you sink, if you’re light enough you
float.

Why is this such a stupid assumption? That's how it works on Earth.

I don't believe that these kids are failing to think; they're using reasonable
analogies, but lacking specific knowledge about the environment on the moon.

>"All science is either physics or stamp collecting." \- Ernest Rutherford

Basically the authors are complaining that the students haven't collected a
specific stamp.

~~~
leoc
Well, the lack of an atmosphere on the Moon should rule out buoyancy. Myself I
don't doubt that many of the wrong answers really were the result of faulty
intuitions or dodgy reasoning.

~~~
jere
Of course, but that's another environmental variable.

------
ghshephard
When I took physics in high school, Gravity was introduced to me with an
equation. After 5 minutes discussion, everyone in the room would have known
how to answer the question about "Dropping a rock on the moon."

I find it hard to believe that a high school physics student, just fresh from
studying gravity module, wouldn't realize that a rock dropped on the moon
would fall down. Doesn't pass the smell test.

~~~
sp332
Being introduced to gravity with an equation is not nearly enough to figure
out how things will behave. It takes calculus to describe the motion of
falling things even without air resistance. Even if someone straight-up tells
the students that gravity accelerates things at the same rate regardless of
mass, they're probably not going to believe it without some experiments.

Edit: a quiz to maybe prove my point :) On the moon, if you throw a rock, what
shape would its arc describe?

Edit2: not a straight line when you drop it, silly!

~~~
qwerta
> tells the students that gravity accelerates things at the same rate
> regardless of mass

Please get your wording right, there is a big difference between force and
acceleration. It is trivial to prove, that things are not accelerated by
gravity at equal rate.

PS: I am not usually wording-nazi but since you started with calculus...

~~~
sp332
You have it backwards, qwerta. If the feather and the hammer fall to the
ground in the same time they must have accelerated at the same rate. Of course
the hammer has more force applied by gravity and the feather has less; that is
why the hammer is heavier!

~~~
qwerta
Yes, but in atmosphere it would be accelerated at a different rate. Stationary
objects are not accelerated at all, because gravitational force is
compensated.

As I was saying, there is difference between force and acceleration.

~~~
Karellen
Interesting.

I read sp332's original comment as having an implicit "in the absence of other
external forces" (gravity accelerates things at the same rate regardless of
mass) as that's often implied when generally discussing forces and
acceleration.

After all, it becomes hard to talk about the relationship between force and
acceleration, if you can't even say that the acceleration of an object is
proportional to a force acting upon it - because there might be other forces
you've not taken into consideration! Yes, I won't accelerate an object if I
try to push it into a barrier, because the barrier will exert an opposing
force that resists my effort. Yes, an object might fall up if I "drop" it,
because it's in an updraft that combined with it's drag coefficient causes
more force up than gravity exerts.

But springing those sorts of situations on people as "gotchas" isn't useful in
a general discussion about the essence of a concept. Unless otherwise
specified, assume ideal point masses in a vacuum (or whatever). If you want to
add opposing forces of some kind to complicate^W make the situation more
realistic later on as a more advanced topic, that's fine, so long as that's
specified up-front.

If complicating factors are not specified up-front, it's assumed that they're
absent, because there are an infinte possible set of complicating factors
which could be present but have not been mentioned yet.

After all, in an atmosphere it _could_ be accelerated at the same rate, as
there's a (previously unmentioned) anemometer and computer-controlled rocket
attached to the object which are set up to produce a thrust which exactly
compensates for the wind resistence! So ner! :-)

(And, in fact, sp332 specifically stated "even without air resistance" to
explicitly constrain the conditions under which their example was valid)

~~~
qwerta
This is not about edge conditions, but about two different concepts. Saying
"gravity accelerates" does not make sense by definition, at least we should
say "gravitational force accelerates".

------
brownbat
On a few sites, a commenter known as "Russ Brown" claims he posted the
original on usenet, referring to a class he took in 1981. He claims that the
quiz results were added to his version of events.

[http://www.openeducation.net/2009/05/07/how-were-apollo-
astr...](http://www.openeducation.net/2009/05/07/how-were-apollo-astronauts-
able-to-walk-on-the-moon-why-heavy-boots-of-course/)

[http://worldofweirdthings.com/2009/04/27/a-gravity-fail-
goes...](http://worldofweirdthings.com/2009/04/27/a-gravity-fail-goes-viral-
but-is-it-real/)

I believe this is the original:
[https://groups.google.com/forum/#!search/"heavy$20boots"$20a...](https://groups.google.com/forum/#!search/"heavy$20boots"$20after$3A1988$2F01$2F01$20before$3A1990$2F12$2F31/sci.astro/nooS8qezfRE/80FcCjnIvDwJ)

------
fosap
I call it bullshit. I just asked that question to a seminar of paedagogic
students, without a single person with physics background. 2 Choose answer the
first answer, 3 the sencond one, the other 20 choose the correct answer. I
expect much better results for students with physics background.

/edit, well bullshit is a bit strong, but replication failed

~~~
mml
Only counts if you forbade them to communicate with each-other.

------
njharman
I'm more stunned by this than when people go around and ask college students
who the VP is or where is France. Those are facts and you either studied and
memorized them or not.

That many people suck at "reasoning" about problems boggles my mind. Most
these students knew the facts of Newtonian mechanics but could not apply them
(in my opinion) to a very simple problem.

Not bragging. I must be good enough at reasoning that I am cognitively unable
to comprehend that other people have trouble with it. Everyone knows how to
breath or think about future. I assumed everyone can take things they know,
combine/apply them to new situations. What I would call reason about things.

Maybe they can. And the results are an artifact of college environment
(study/memorize/pass test vs actually learn/challenge/grow).

See, I so can't comprehend it that I'm trying to come up with
rationalizations.

------
buyx
Does a lack of knowledge of physics really matter in the real world for most
people?

I was recently wondering if our terrible road safety problem in South Africa
can partly be explained due to a lack of understanding of physics. After all,
intuitively Newton's First Law explains why seatbelts are necessary. Concepts
like momentum and kinetic energy explain why heavy trucks, speeding down steep
inclines are dangerous - authorities don't seem to grasp that very often, and
tragedies involving runaway trucks on poorly engineered roads are not
infrequent.

But I then realised that two of the most reckless drivers I know are my uncle,
an Engineering dropout, and my friend who is a practicing engineer. Being good
at physics hasn't saved them from being in multiple car crashes.

Are there any cases where an understanding of physics helps the average person
in everyday life?

~~~
waterlesscloud
This reminds me of my reaction to the evolution/creationism debate- Does it
really matter which one people believe? It has pretty much zero practical
impact on their lives, and there aren't a lot of decisions they can make for
others that depend on the information.

Now, I'm not in favor of teaching creationism in schools. Schools should teach
what we as a civilization understand to be true. But as far as what
individuals choose to believe? I don't really much care. I think it's an odd
thing to get emotional over, but both sides certainly do (this is me
preempting emotional replies :-) )

Of course, even when evolution is taught, it's almost always taught wrong.
Even a large percentage of graduate biology students have deep misconceptions
about what evolution is and how it works.

It just occurred to me that machine learning students would probably have the
best understanding of evolution of any group of students. Ha!

~~~
EliRivers
If you choose creationism, you also choose the existence of a creator. A great
many people who hold this belief seem to base many decisions in their lives on
what this creator would want them to do (or at least, say they do). This can
be a very, very long way from "zero practical impact on their lives".

~~~
dennisgorelik
Could you give an example of practical impact on life of person who chose to
believe in creationism?

~~~
EliRivers
A literal belief in fairy tales leading to them making major life decisions
based on the collected, millennia-old edited ramblings of a desert tribe.
Start with lynching witches and go from there.

------
essayist
I can't find the reference now, but in the 1980's, there was a study done on
honors physics students -- undergraduates IIRC -- at Johns Hopkins. They were
asked questions that they had the physics training to answer, but that were
not problem set or exam questions. For instance: Coil a garden hose in a
spiral, then force a ping pong ball out through the hose from the center to
the periphery with a blast of air; how does it move once it leaves the hose:
(a) continues in spiral (b) straight out - the tangent of the spiral where the
hose ends (c) bending outward, away from the spiral.

Some large percentage of the students got it wrong. Explanations: (i) students
limited their "physics know-how" to the textbook context, and this was
something different; (ii) textbook problem sets are, over time, edited to weed
out confusing problems, even if they're valid.

I've encountered something similar in teaching basic financial present value
analysis to engineers - even the students who do well in the class go back to
"folk" thinking when we discuss their mortgages and credit cards.

To me, it says that the cue of the classroom, or the awareness that "this is
part of Physics 101" is critical to getting some people to apply a particular
frame, and without that cue, they go back to "common sense". That does explain
what happened (in the blog post) in the Philosophy class, and in the phone
poll, but not as well what happened when the blog author tested her physics
students.

~~~
sb23
Well shit, now I want to know the answer. It's "straight out" right?

~~~
quasse
From a simple F=m*a standpoint maybe, but I'm thinking that the hose would
probably put a spin on the ball so it would likely curve outwards?

A ball with no spin on it would travel straight outwards because there would
be no force acting on it to make it curve in any other direction.

I think a ball with spin on it would curve outwards because the ball would
rotate the air around itself, which would provide the force needed to
accelerate it outwards.

------
DateK
One explanation for the wrong answers is how people use the phrase 'pen
floats', and how people are imprecise about using words.

The gravitational constant is 1/6 of the Earth's. This means that I can jump
on the Moon 6 times higher than here and the pen will tale 6 times longer to
fall down.

It will take 6 times longer for gravity to 'kick-in' and cause the perceivable
movement, as we got used to here on Earth - where on Earth the pen moved
already 6 cm on the Moon the movement is still 1 cm.

It looks as if the things are moving slower. I can catch a falling egg before
it reaches the ground, my reactions are like of a fly on Earth.

So I can say that the things are floating on Moon, because they are not
accelerating and falling fast enough, in common terms. In interstellar space
the pen will fall onto the neighbor galaxy, but will do this so slow, that I
will perceive as if it is floating. If the pen will move alongside with an
object much smaller than the Moon (a rock), the pen will fall onto the rock
with much slower acceleration. For time perception of humans it will float in
space.

Another explanation for wrong answers is that if you feed people with stupid
questions, you will get stupid answers. Have you asked me to answer these
questions I will surely answer wrongly 'pen floats' and 'heavy boots' on
purpose only to prove the point. These answers seem to be serious enough to
mislead you.

~~~
kens
No, it does not take the pen 6 times longer to fall down on the Moon compared
to Earth. Not even close. That's not how acceleration works. [I can give the
equation, but I think it's more instructive if people think about it
themselves :-) ]

Also, actually try dropping a pen, like right now. Gravity "kicks in"
immediately - there's no perceptible delay. (Unless your perception is way
different from mine.)

~~~
dennisgorelik
I suspected that time difference between falls would be not linear, but I was
not sure about actual ratio.

Playing with freefall distance equations showed that time to fall difference
is square root of 6. Here we are:

    
    
      Height = gEarth*timeOnEarth^2/2 = gMoon*timeOnMoon^2/2
      gEarth = gMoon * 6
      6 * gMoon * timeOnEarth^2/2 = gMoon * timeOnMoon^2/2
      6 * timeOnEarth^2 = timeOnMoon^2
      timeOnMoon = sqrt(6 * timeOnEarth^2)
      timeOnMoon = sqrt(6) * timeOnEarth = 2.45 * timeOnEarth

------
hrvbr
There's a similarity between teachers and journalists in that they're supposed
to double-check their informations before transmitting them. Not doing it
plagues society.

------
brownbat
Towards the end, there are some guesses as to what theory of gravity the
students hold, if it's a buoyancy analogy, or a threshold theory... A lot of
people don't really subscribe to any coherent system of the world at all.

When you press someone, it's not uncommon for them to just pile on another
fact about the subject matter and reassert the claim.

It's like brute force puzzle solving, kind of like I used to do in adventure
games - you know the result you want, juggle all the stuff in your inventory
or mind until it works.

And for a lot of subjects, for a lot of education, that approach works really
well. You're told three facts about some historical event. You're asked a
question on a test about the event. List one of those facts to win.

I'm guessing they jump to "boots" because the bootprint on the moon is a
pretty widely seen and memorable image, and boots in our normal life are
sometimes heavy. Heavy things make it harder to float, that's what heaviness
sort of means. Having arrived at "floating's hard," they then call it a day
without really understanding anything about how they got there.

There's no underlying theory, they kick away the scaffolding as soon as they
get to any answer.

People don't have a list of facts in their heads that are constantly checked
for mutual consistency, and people can stubbornly hang on to any premise they
want.

In other words, the students (+ phil TA) aren't just stupid on this point,
they are so stupid, the physics teachers don't even understand how stupid they
are.

------
ivan_ah
I think the false association in this context is the following:

    
    
        space -->  weightlessness
    

Thinking this makes people look for "alternate" explanations, like the weight
of the boots, etc.

People who have not been trained in physics often have a different "intuition"
about the laws of physics. An interesting effort to qualify these "physics
misconceptions" is the Force Concept Inventory (FCI) questionnaire[1], which
which asks students to answer some basic qualitative problems from Newtonian
mechanics. You should try it and see how you fare...

Interestingly, researchers have found that even after taking a Newtonian
mechanics class, many students still hold on to their misconceptions---their
score on the FCI is only slightly improved...

[1] [http://prst-
per.aps.org/multimedia/PRSTPER/v3/i1/e010102/e01...](http://prst-
per.aps.org/multimedia/PRSTPER/v3/i1/e010102/e010102_app.pdf)

------
b3tta
And that's my basic problem with talking with other people: It's hard for me
to understand how one can not know or comprehend what I know and classify as
"basic knowledge"...

Of course I understand that and can for instance explain it to them, but it
often still remains surprising for me.

------
mml
My wife posited that perhaps their gravity suits kept them on the ground
(which i found charming, at least she was thinking of gravity, and/or science
fiction). My 8 year old daughter thought for a second and said the rock would
fall, then on her way out of the room said it would float (no doubt taking
some time to catalogue everything she's ever seen or read about space). I'm
fairly sure if the question were posed as multiple choice, they both would
have answered correctly.

No indictment of either (or anyone else who would answer incorrectly). After
all, not many people think of physics very often on a day to day basis,
particularly physics of extraterrestrial bodies.

------
moo
I could have benefited from an unhurried, contemplative learning about science
in elementary school. The primary concern approach with example and counter
example even seems fun. The "heavy boots" problem of focusing on what is not
the primary concern is a problem in understanding other issues like in
politics. In politics though people have a self interested agenda and will
warp reality to make it fit like having the earth the center of the galaxy.
People should strive in political learning to use the first principle approach
of the article, like eliminate oppression, and unbiasedly apply it
universally.

------
mnw21cam
A long while back, I read a scifi book (really a kids scifi book) about a kid
that finds a red pebble which cancels gravity for anything it's in contact
with (except kids, obviously), causing those objects to be pulled strongly up
into the sky. Why? Because they were attracted by the moon's gravity. They
even got it to spin round and suggested using that for free energy. Can't for
the life of me remember the title or author, but I remember it really grated
against my sensibilities, and I never read anything by the same author again.

~~~
teahat
Pretty sure it was Antigrav by Nicholas Fisk. It was a cool story - if you
were a kid. I never did find any red pebbles though.

~~~
mnw21cam
That sounds about right.

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foobarian
When I read the title I thought this would be about space walks. Having heavy
boots would help create a greater gravitational attraction to the space
station, making it harder to float away.

It's interesting to consider the forces involved. At 10m, with a 100kg
astronaut and a 15 ton space station the gravitational force is about 1e-7
Newtons. At that acceleration, if the astronaut kicked off at the speed of
1cm/s--or 36 meters per hour--and assuming the force doesn't change, it would
take about 24 days to get back.

------
gmoot
Here is a related question that has bothered me for some time: in Jules
Verne's "From the Earth to the Moon" (1865), he writes the travelers as only
achieving weightlessness for a small moment, at just the point where the
moon's gravity exactly cancels out the earths gravity.

This makes an intuitive kind of sense: you would gradually lose weight as you
get farther from earth, then after a moment of weightlessness gradually 'gain'
weight as you approach the moon.

Obviously this is wrong, but why?

~~~
matthewmacleod
(I'm not a physicist, so take the following with a grain of salt!)

It's not wrong, but it would never happen.

Let's say we've built a moon elevator. Like a space elevator, but tethered to
the moon. You travel from the earth; there is a brief period of acceleration,
then you settle down to a steady speed for your journey.

After you reach the steady state, you are going to experience normal Earth
gravity. As you move further from the earth, however, you will experience less
of it. As you approach the moon, its gravity will eventually be stronger -
with this transition occurring at the Lagrange point L1 between the earth and
the moon, where the gravitational pull from each is equal.

In practice, until we build a moon elevator, this isn't going to happen.
Instead, we have to throw you at the moon using a rocket. Most of the energy
we use for this is actually spent making you go sideways, instead of directly
up. It's kind of cool actually - if you are orbiting the earth in, say, the
ISS, you are actually experiencing nearly the same gravitational pull as if
you were on the surface. You are just moving so ridiculously quickly in a
circle around the earth that the centripetal force cancels out gravity - like
someone is swinging you around on an invisible rope. Since this is happening
to both you and the spaceship you are in, there is no relative acceleration -
so you appear to be weightless.

If we fire some more rockets to accelerate you towards a lunar orbit, nothing
else changes - you are still not accelerating relative to your spacecraft
(assuming you are strapped in!) and so you continue to appear weightless. You
transfer into orbit around the moon - and you are in the same situation you
were in when orbiting earth. But if you drop a lunar lander, which slows
itself down - it'll fall!

Orbital mechanics and gravity can certainly be counterintuitive, but it's
thoroughly fascinating.

------
dennisgorelik
If 47% of students fail that "pen on the Moon" question -- that means that
about half of professionals are clueless about physics.

On the other hand, most professionals are quite functional in their role (if
it wasn't the case, why would employers pay them?).

These two observations mean that understanding of physics is not mandatory for
being functional professional.

~~~
informatimago
No, it means they're not functional, and that employers pay them to heat their
chairs. Why else would employers insist on having people come to the office,
instead of working at home, as we almost all could, in this day and age?

Further: [http://www.technologyreview.com/view/519241/report-
suggests-...](http://www.technologyreview.com/view/519241/report-suggests-
nearly-half-of-us-jobs-are-vulnerable-to-computerization/)

------
downer95
That entire article made me angry like when I hear about creationism and
evolution being taught as equal theoretical concepts.

------
7402
Great video of Apollo 15 astronaut dropping feather and hammer on the moon:

[http://youtu.be/03SPBXALJZI](http://youtu.be/03SPBXALJZI)

Too bad this isn't part of current events any more.

------
jeena
Fascinating, I was so confused at first because I first misunderstood the fact
who was right and who was wrong in this philosophy class.

I will ask this question on parties, this will be funny :D

------
stcredzero
I wonder what the poll percentages would be like in other countries? I suspect
that fewer people would be this ignorant in industrialized countries other
than the US.

------
robmcm
This is why Super Mario Galaxy is a great educational tool!

------
novaleaf
it blows my mind that half got the first question wrong... :(

------
aaron695
Myth: This story

Truth: There are dumbasses in this world... those who believe this story,
because it gives them a superiority over (mythical) others.

Lol, those stupid uni students who don't even know there's gravity on the
moon. Lucky I didn't get a degree and become dumber/Lucky my Uni was better.

It's even a friend of a friend of a friend.

Seriously, why is this on the front page?

