@TasteTheFlava:
damn, i was hoping i was the only one who caught the reference.
@OMG!!! Ponies!!!:
yeah, dope reference man.

nutbastard

@mtopper:

speaking in pressures is just fine as this is an ideal gas and the two are directly proportional (there's no temp difference at play here). intuitively you know this to be true, since when the system stops accelerating what else is to bring the air back to an even distribution inside the cabin?

esadun

@OMG!!! Ponies!!!: McFly!!!!

TasteTheFlava

@mtopper:

when purchased at best buy, perhaps?

arsenal4

@DWD:

since when do boxes of cards contain rocks?

mtopper

@m4ximusprim3:

Not pressure, DENSITY - (everything in the car is at the same pressure).

The difference in the DENSITY of air (more denser) vs the DENSITY of helium (less dense) causes the baloon to move in the opposite direction than the air in the car. The cars moves on startup but the air (like the people in the car) doesnt start up as quickly and moves to the rear. The baloon which is LESS DENSE moves in the opposite direction.

When the car slows, the air does not slow as quickly and moves to the front of the car. he baloon moves backweard because it is less dense than the air.

Marty

mtopper

@DWD:

Of course it's incredibly obvious. Any physicist with even a remedial background in physics, motion basics, rocket science, or basket weaving could have figured it out. *SIMPSONS DR Hibbert SCIENTIST ACCENT*

That's why this has generated so many comments. Any YES we all think your very smart now. FFS *Rolls eyes*

Out2gtcha

I thought everyone knew this is how it works. I did a demp of this in 6th grade, for the science fair. Who knows I ended up winning, LOL

HJTravels

I'm not the brightest rock in a box of cards, but this seemed incredibly obvious to me back in physics class when we did it with a ball tied to the bottom of a jar filled with water. Same with a bullet being fired horizontally and one being simply dropped from your hand at the same time, of course they hit the ground at the same time. First year physics was great...after that a nightmare. I must have missed the cartoons that warped most people's concepts of basic physics.

DWD

@IUSEAMACSOSUEME: i loved that show. until i saw an inconvenient truth, i used science i learned on that show as my reasoning for not believing the melting of the ice caps would raise sea level. but al gore taught me there is land under there.

EMoShunz

1986: 7am, Cheerios, Mr Wizard....that's how to start off a morning.

IUSEAMACSOSUEME

I didn't know nerdy scientists would drive (or could afford) Land Rovers. . . especially ones who specialize in balloon moveology.

stonecoldcleric

@OMG!!! Ponies!!!: few reasons, mostly familiarity. i use konqurer on my kde boxes, which is the code base for safari on my imac, so for here it just was to make me comfortable. that and i like helping out by submitting bug reports. you are right though, ff is the best, but not stable on mac or linux, and on bsd i have to run it in wine which isn't stable either.

EMoShunz

@EMoShunz: Safari on XP? Why?

I use Safari on Mac, but only because Firefox still isn't stable (tired of FF crashing 3x/day). Safari is a good alternative browser, but you have access to the best there is.

OMG!!! Ponies!!!

BEGIN OMG SPOILER

@EMoShunz: You know how, as you accelerate, objects tend to move towards the back of the car? That includes the denser air, and that causes the not-as-dense balloon to move forward. Apply similar reason to turning and stopping the vehicle.

END OMG SPOILER

dsevil

@OMG!!! Ponies!!!: @m4ximusprim3: thanks guys. i try to use safari on my xp system at work, but it's not quite as good as it is on leopard at home.

EMoShunz

Thats cool...he reminds me of that teacher you have that was always nice that you wont ever forget...I wanna be edumacated

Kamenwati

@EMoShunz: Its actually pressure differences- as you accelerate, the air tries to stay still and "piles up" in the back of the car. Therefore, the air pressure on the back of the baloon is less than the front, so it moves forward.

I wonder how fast you'd have to accelerate downward to make a helium baloon not float?

m4ximusprim3

Lol Winnie the Pooh & Tigger!!

simpsons-movie-ruled

@EMoShunz: Close. Air density. What makes the balloon float (helium being less dense than air) causes the balloon to travel in the opposite direction as the rest of the occupants of the car.

I am your density... I mean... your destiny.

OMG!!! Ponies!!!

i can't get the (video?) to work, just a blank square. oh well, i'm guessing it has to do with pitch and roll (i.e. when you accelerate the front of the car lifts so the balloon moves towards the higher part).

EMoShunz

If I knew there were professors like that, I wouldn't have talked my way out of having to take physics and chem.

Who am I kidding? I still would have. I hate mathematics. Math is for girls.

OMG!!! Ponies!!!

I always wondered why that happened. Thanks, quirky beard science guy!

homerjay

you know america's at an all time low when winnie the pooh is in the witness protection program...

arsenal4

Somebody's kooky uncle just blew my mind.

thisaintsweettea

Yes, I learned a long time ago that true genius is the ability to make complicated things uncomplicated. Not learn to speak in ways / terms that no one understands. The lone exception to this rule is that genius in comments require obscure references that almost nobody gets.

OldSchoolGadgetLover

Another simple way to look at this example is the balloon is the same as a 2 liter bottle of coke, half filled... The air in the bottle is the helium balloon in the car... and the coke represents the air in the car.

When you go forward, the coke goes backward in the bottle, and the air is pushed forward in the bottle by the coke.

The air in the car falls backward in the car, and the helium is PUSHED forward by the air (which is what actually happens... it is PUSHED)

Completely intuitive result.

dcartist

In the first example, I meant to write "balloon goes forward (UP)", sorry.

dcartist

That's inside the car only, right? It makes perfect sense.

Pretend the car has no windows and you can't see outside. When you accelerate, it feels like the car has suddenly been tipped on its back because you (and everything in the car, including the air and balloon) are tugged back... keys in your hands are pulled back, as if the back of the car were facing the ground. Thus if the back of the car is DOWN, the front of the car is the new UP, and the balloon goes back (UP)

Same when you turn right, it feels like the car has been tilted on it's left side, so left becomes the new DOWN, which means right becomes the new UP, and the balloon goes right (UP).

according to Einstein, gravity and acceleration are indistinguishable.

dcartist

@dcartist: Beakman's World?

OldSchoolGadgetLover

@evan394: Huh??? Oh well, being misunderstood is what I do best. I love obscure references to cool old movies. Really.

OldSchoolGadgetLover

Helium assisted Inertial Dampers, here we come!

dna

@OldSchoolGadgetLover:

Yeah, I guess an even better example would have been an air bubble in a snow globe sitting on your dashboard...

This stuff reminds me of the great Billy Nye's show, and that other dude, the Jewish guy with the loud voice and the cute, brassy assistant, and a dude dressed up as a big fat rat (anybody remember the name of the show from the 90s I think?)

dcartist

I love science. Not very practical, but fun nonetheless.

jawzxy

@OldSchoolGadgetLover: Ok, you're selling all of us that were born before 1980 a little short by saying "obsuce references that almost nobody gets". The words "old school" are in your screen name but you complain that somebody made an incredibly obvious Crispin Glover from Back to the Future referense. Shame on you, butthead. Basically what you're saying is "sorry I'm too smart to get your simple-minded comments". Lighten up.
@nutbastard: Don't kid yerself dude, you weren't the only kid on the block with a vcr and/or HBO in the 80's.
@OMG!!! Ponies!!!and TasteTheFlava: Keep the ref's coming, I'm McLovin it.
@stonecoldcleric: "baloon moveology" laughing my ass off, no shit I was literally rolling on the floor laughing my ass off.

evan394

@dcartist: I like your second analogy way better than your first. It's easier to follow.

The real counter intuitive part of video with the balloon had to do with the common misconception that air is so light it doesn't have enough mass to push things around. The guy in the video did a good job at pointing that it can and does when lighter stuff (like helium) is around.

OldSchoolGadgetLover

@Out2gtcha:
Oh, no, no, no, was not trying to imply that I am smarter than the the average Giz reader, in fact the contrary is probably true...I pointed out how advanced physics was a nightmare...only that for some reason plain old Newtonian physics totally made sense without any explanation, I was constantly saying "of course" when everyone else in class was saying "wow" or "no way." Those same people blew me away when things got harder in the upper level courses. See how stupid I am...I can't even get a simple point across.

@mtopper:
Ummm...that's the point, they don't go together.

DWD

I think the best way to explain it is just what it is. Any analogy just makes the concept more confusing since it's such a simple concept to begin with.

Helium is lighter than air so when dense air moves in one direction the helium wants to move in the opposite way.
That's why a helium balloon floats to begin with. Air is denser on the ground than in higher altitudes and the helium is lighter so it goes up.

zephyr_words

@stonecoldcleric: They're exactly the kind of guys who can buy this things without resorting to "credit"...

@OldSchoolGadgetLover: This is exactly what being intelligent (and intelligible) means.

@jawzxy: GlaDOS would not agree with you... Science is what made McGyver what he was back in the day (not McGrubber, McGyver!).

whiskey

What was the purpose of the passenger in this experiment?

exigent

I'm not sure I agree. The balloon is basically in suspension, and not really anchored to anything, even with the string tied to it. If you tossed a ball up in the air in a car, and took a turn, would it land in the exact same spot you threw it from? The ball should act independently of the car because the movement is relative to the car and the earth, but not the ball. I would think the balloon would respond the same.

secretmanofagent

I really liked that. I'm a pretty smart guy and until he explained that it was different densities causing it to move in unexpected ways I was a little stumped.

He explained it in a very down to earth kind of way. I love teachers who are like that. He makes me miss Mr. Wizard. God I loved that show when I was a kid.

The same principle that makes a helium balloon float is the one that makes it move differently. It really is counter-intuitive till you understand that.

ed207

Is that the guy from the movie HEAT?

pj737

is this news? more like preschool physics. This was taken out of a kindergarden video, wasn't it?

citizen024

I remember seeing this on TV many, many years ago when I was a kid...

I think it was on Fight Back...

Bobby T.

@Bobby T.:
Holy crap...........doesnt really have anything to do with this thread, but does anyone else remember "Fight Back"? and/or the reason why anyone actually watched it?

Out2gtcha

@DWD:

TY: Clarification good. School bad. I are good at advanced fisiks too.

Out2gtcha