Scientific Error Spreading:

A McDonald's wrapper informs us, "In space, you can jump six times higher." Only in those parts of space (which are often not even thought of as quite "in space," though I suppose under some definitions they qualify) where the gravitational field is quite right.

Thanks to this site for confirming the text (I failed to save the wrapper, so I'm working from a two-day-old memory), and for getting there first.

In space, which way is up?
8.12.2006 4:29pm
noahpraetorius (mail):
In space, assuming no inhibition by a space suit and jumping from a platform equal to your own mass then you and the platform would recede from each other at roughly the maximum upward velocity you can achieve on earth. From then on it is simply a matter of elapsed time since you have far exceeded the escape velocity of the platform.
8.12.2006 4:56pm
Ship Erect (mail) (www):
Six times higher or ten times lower?

The more grievous scientific error is the assumption that McDonald's is food, though perhaps EV, disgusted, just looked at the wrapper and tossed the "hamburger." Living in NYC, the land of amazing one-off fast food restaurants of every nationality and ethnicity, I am always amazed by the long lines at McDonald's.
8.12.2006 4:57pm
TO (mail):
Oh, the horror. First they try to make the poor kids obese. Now they're trying to make them ignorant, too.
8.12.2006 5:56pm
volokh groupie:
McDonald's probably meant to put 'on the moon, you can jump six times higher', which is accurate becuase the acceleration due to gravity there is about 1.6 m/s^2 or nearly 1/6 of earths. Still no excuse for the bungling up of science though.
8.12.2006 6:15pm
Peter Wimsey:
Perhaps obesity is less of a problem if the gravity is only 1/6 as strong.
8.12.2006 6:39pm
Bob Woolley:
A society that relies on McDonald's wrappers for science education deserves whatever it gets.
8.12.2006 7:08pm
Ron Hardin (mail) (www):
It's TV news science. They picked it up from CBS shuttle coverage, probably.

My favorite part of the voyage is when they're outside the earth's gravitational field.

That's when you need velcro.
8.12.2006 7:15pm
Ron Hardin,

The Earth's gravitational field extends out over one million kilometers. I believe the shuttle operates within one thousand kilometers. The Earth's gravitational field is not significantly weaker at that distance.
8.12.2006 8:04pm
John Jenkins (mail):
At 400km the strength of the Earth's gravitational pull on an object is about 89% of the same pull at sea level (approx 8.7 m/s^2). You need Velcro when in orbit because you're in continuous free fall (your acceleration in the opposite direction is also approx 8.7 m/s^2) so your effective weight is 0.

If the Earth's gravitational field weren't there, you couldn't maintain a state of continuous free fall and you'd just shoot off into space without constantly adjusting your direction with some kind of thrust.
8.12.2006 8:28pm
elChato (mail):
John Jenkins:

you seem to have knowledge so I'll ask you: why, when the astronauts spacewalk, are they not separated from the shuttle? (somehow this question has stuck in my mind lately.)
8.12.2006 9:25pm
Aric (mail) (www):

1) They're usually tethered, though there is the Manned Maneuvering Unit that is self-contained and not tethered.

2) There's nothing pulling them away from the shuttle.

If an astronaut, untethered, were to decide to jump away from the shuttle, he'd enter a slightly different orbit than the one that the shuttle is in. Depending on the direction of the jump, he might enter an orbit that intersects the shuttle's every 45 minutes (and therefore be rescuable), or much more likely, enter one that only intersects the shuttle every few weeks or even few months.

On the other hand, the shuttle does have some (but not much) maneuvering capability, so if he did jump, have a thruster malfunction, or whatever, they could go grab him.
8.12.2006 10:23pm
I agree with Volokh groupie -- they're thinking of the moon.
8.13.2006 12:20am

why, when the astronauts spacewalk, are they not separated from the shuttle?

Your question may be generated by the difference between the atmosphere at the earth's surface and the atmosphere at shuttle orbit.

If you step away from a massive object like a train, the train keeps moving forward while you fall behind. This is for two reasons: 1. the train is continuously applying power so that air resistance does not slow it down, and 2. you do not have any power to apply so the air resistance to your forward motion slows you down dramatically. Nevertheless for a brief moment after you step off the train, you maintain position with it, then air resistance slows you down.

In orbit, there is very little air resistance. As a result, the shuttle does not continuously apply power to maintain the same velocity, it merely relys on the power it had applied earlier to get it in orbit. Similarly, when the astronaut steps off the shuttle, there is no air resistance to slow him down, so he simply maintains position with the shuttle.
8.13.2006 12:46am
Syd Henderson's Cat (mail):

In space, which way is up?

In space, which way is down! Which way is down!
8.13.2006 12:15pm
Kevin L. Connors (mail) (www):
We might also consider the compositional error as well: In space, we have no predetermined frame of reference from which to measure "height."
8.13.2006 1:17pm
tefta2 (mail):
TO (mail):
Oh, the horror. First they try to make the poor kids obese. Now they're trying to make them ignorant, too.

Wrong order. They* made them ignorant first, so they could make themselves fat.

*The teachers union controlled public schools.
8.13.2006 1:41pm
Adam Holland (mail):
In one can hear you belch.
8.13.2006 9:23pm
loikll (mail):
The sad thing is, this burger-wrapper copy was written by some female college graduate working in marketing or at an ad agency, who has no idea what's wrong with the statement. She no doubt has a background in journalism. (I'm just speculating but there's a 99.5% chance I'm correct.)
8.13.2006 10:53pm
Chip Morningstar (mail) (www):
Reminds me of an oldie but goodie: Heavy Boots.
8.13.2006 11:51pm
Doug Sundseth (mail):
Even if the wrapper was supposed to refer to the moon* rather than "space", it is, of course, incorrect. On the moon, you can jump five times higher (or six times as high).

(Yes, yes, I know.)

* For purposes of this discussion, please assume that "the moon" refers to Earth's principal satellite, also known as "Luna", rather than some other moon. (There's a "The Tick" joke here that I'm conciously not making, BTW.) (Of course, I'm slyly referring to that joke to make you think it's better than I'm sure it would be were I to actually make it.) (But then I'm spoiling that by making a meta-comment about its lameness.) (But the meta-comment is a joke in itself.) (You might notice a recursive theme here.)
8.14.2006 12:26am
Dustin (mail):
The statement on the wrapper is logically necessary.

You do have the potential to jump six times higher somewhere in space.

At Six Flags, you can ride a wooden roller coaster.

Bu bu but, only if you are at a wooden roller coaster!! There are metal ones, too!

Still, the statement is true.
8.14.2006 2:36am
JAM (www):
I came across this same silliness on a McD's bag a couple of weeks back when I was there with my son. I used it (as I often do with such things - see below) as a teaching moment to discuss why the statement was wrong. Such things are useful in that sense.

Quite some time ago I had a minor fit regarding a toy they distributed promoting the movie Robots. It was a little "action figure" of one of the characters, along with a metal plate that he could be displayed on. According to the instructions that came with the toy, when the character was positioned on the plate, a light on his head would "magically" light up. I found a delightful irony in the fact that they would have a toy robot - an icon of high technology - and still refer to a simple electrical circuit as "magic." That was another teaching moment.
8.14.2006 10:01am
Zubon (www):
On Earth, you can jump eight feet straight up (if you are a puma).

Also, if we get to use the "those parts of space" qualifier, Earth is very clearly in space. In space, you can jump six times as high as you can jump in space.

On Earth, you can swim twenty times as fast! (comparing those parts of Earth that have water to those that have somewhat dense mud)
8.14.2006 11:55am
Crunchy Frog:
Be careful to not conflate viscosity and density. A human body could not swim in dense mud, but would float on top of it. A material with high viscosity, but a density roughly equivalent to that of water (90-weight motor oil, perhaps?) would be commensurately harder to swim in.
8.14.2006 3:06pm
loikll - Why female? [*bristling*] I understand that more men than women are attracted to the sciences, but not so many that one can assume a journalism major working in marketing or advertising (i.e., a scientiphobe) is probably female. Women have no monopoly on scientific ignorance.
8.14.2006 7:16pm
Nick Husher (mail) (www):
Syd Henderson's Cat: The enemy's gate is down. Duh.

Re: gravitational fields
Gravitational fields extend infinitely in all directions at some strength or another. The force of gravity at a distance R can be approximately described by: G = 1/R^2

For G to be zero, R^2 must be infinite.
8.15.2006 4:41pm