3047: Rotary Tool

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High Altitude Cooking Instructions

|< < Prev #3187 (December 29, 2025)

Title text: 1,300,000-1,400,000 ft: Ask a crew member to show you how to use the ISS food warmer.

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Explanation

This is one of 61 incomplete explanations: This page was created by a crew member using the ISS food warmer. Don't remove this notice too soon. If you can fix this issue, edit the page!

At higher altitudes, cooking experiences extra complications. This was previously mentioned in 2153: Effects of High Altitude. This comic imagines food preparation instructions with additional caveats specifically for high-altitude cooking.

A part of these instruction is thus labeled High Altitude Cooking Instructions. It is unclear if this is the package with the dish, or if it is a board placed on the wall of the kitchen (of maybe some kind of vehicle, maybe a space capsule).

At the top there are a part of these instructions that can only partly be seen; presumably, these are the "sea level" instructions mentioned later. What can be seen for sure is "remove from" and "for 3 minutes before serving." A qualified guess is that it says "remove from heat for 3 minutes before serving," but as nothing above this is visible, it is impossible to tell what the meal is, and the original cook time and temperature can only be estimated. Below follows the separate High Altitude version, which list instructions for three different heights above sea level.

While the first two sections are reasonable accommodations, given the lower boiling point of water under less pressure, for altitudes of 3,500-6,500 ft (1-2 km) and 6,500-9,500 ft (2-3 km), the instructions - as is typical for xkcd - soon veer into absurdity.

At an altitude of 250,000-450,000 ft (approximately 76-137 km), the instructions assume the user is partaking in some kind of controlled spaceflight. The "cooking instructions", therefore, are instead instructions for reentry; basically, telling the user "You can wait until you get home".

In this range of altitudes, you are highly likely to actively be either on the way down or, perhaps, still on the way up to space; cooking shouldn't be your primary concern in either case. The air-launched X-15, as did the later SpaceShipOne, ultimately 'flew' at around 350,000 ft, though (as with rockets, re-entry capsules or projectiles) there is no real capability to loiter at these altitudes, being well above even the unmanned balloon-flight record or that of any sustained level flight. And only in the latter might you even expect to be a passenger, not too busy to enjoy a light pre-prepared snack — already cooked, as necessary, at ground level.

Once back on the ground it tells you to use the Sea level cooking instructions. These are most likely the one that is written on the top part of the comic.

The title text goes a step further and assumes that the user is in orbit - specifically, on the International Space Station at an altitude of 1,300,000-1,400,000 (396-426 km) (The ISS is between 413-422 km above Earth's surface). Anyone on an orbiting space station is presumably going to be on that space station for an extended period, so they cannot wait until after they return to Earth for a meal, so the "cooking instructions" simply direct the user to someone who can show them how to use the on-board facilities. Even if the pressure is one atmosphere, cooking with boiling water in a microgravity environment (as one might experience on a free-falling space station) is likely not the best of ideas, so better ask someone for directions.

Interestingly, just below the 1,300,000 feet limit, you may instead be able to ask a Taikonaut how to use their microwave or recently installed air-fryer.

In 2022, spaceman extraordinaire Scott Manley uploaded a rigorously scientific presentation titled Can You Cook a Turkey by Dropping It From Space?. A similar question was discussed in the 2013 What if blog post, "Steak Drop".

Transcript

[Two notes, of black writing on white background, are printed upon an item of grey packaging that is shown in closeup, slightly inclined and rotated within the comic panel. Only the latter parts of the top note are visible — because of the slant, only the first few characters of the penultimate line, and the entire final line of text, can be read. The bottom note is fully visible, as the bottom of the board is all within view.]

[The readable part of the top note's two lines:]

Remove fro...

for 3 minutes before serving.

[The bottom note:]

High altitude cooking instructions:

3,500-6,500 ft: Add ½ cup water, increase cook time to 12 minutes

6,500-9,500 ft: Add 1¼ cups water, increase cook time to 18 minutes

250,000-450,000 ft: Orient reentry vehicle for aerodynamic stability. Deploy parachutes at 10,000 ft. Descend, keeping crew capsule tightly covered, for 3-4 minutes. After splashdown, follow sea level cooking instructions

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Discussion

How come it's at 0.017 RPM for a minute?? and yet 1 RPM for a second? pls fix this randall Midnightvortigaunt (talk) 18:01, 5 February 2025 (UTC)

Its 0.017 RPM for the minute hand. The minute hand revolves once per hour or at 1/60 RPM ≈ 0,017 RPM --172.71.148.59 18:14, 5 February 2025 (UTC)

Ohhh that makes sense I didn't think about it like that Midnightvortigaunt (talk) 19:27, 5 February 2025 (UTC)

Mr.Dude (talk) 17:20, 7 February 2025 (UTC) I wonder what torque is needed to launch the average backyard telescope worthy of a tracking mount at Mach 8 given standard state pressures and temperatures of perhaps average conditions found in Randall’s back yard.

How come the comment above is invisible to me? 172.68.245.229 18:03, 5 February 2025 (UTC)

Possibly because people indented with spaces rather than with colons? 162.158.79.77 19:40, 5 February 2025 (UTC)

72 RPM for a record player...? 162.158.74.25 18:08, 5 February 2025 (UTC)

I could only find 78 RPM disks in the german wikipedia. 172.70.114.56 18:41, 5 February 2025 (UTC)

I came here to make the same comment: 72 is most probably a typo. The old records (at this date, very old, since the transition to vinyl records was 1948 to 1958 (in the US)) were 78 rpm, not 72 rpm https://en.wikipedia.org/wiki/Phonograph_record Rps (talk) 19:30, 5 February 2025 (UTC)

72 is (for example) relevent to font sizes (size 1 = 1/72 of an inch, size 72 = 1 inch), which might therefore have envaigled Randall's head for numbers by a different route, and got him confused. Conceivably he has had to deal with playing old 78s, but probably not for a long time... even the retro-revival of vinyl, recently, has probably not had quite so many old old records released to fill such nostalgic needs. So an easy brain-fudge/thinko to trip over on. 162.158.74.48 00:54, 6 February 2025 (UTC)

There used to be a record label call 72RPM records. 172.69.229.146 (talk) 19:07, 5 February 2025 (UTC) (please sign your comments with ~~~~)

We need one of those tables in here. DollarStoreBa'al (talk) 18:37, 5 February 2025 (UTC)

I made a change to the explanation that all of these numbers are realistic because, I checked out the speed of dental drills and they really do rotate that fast. I haven't checked out all of the other tools, but I suspect that they are also accurate. If you find that any of them are misstated, please correct my correction. Rtanenbaum (talk) 22:38, 5 February 2025 (UTC)

TABLE REQUEST When someone uploads a table, I'd like to recommend a second column for the frequency / reciprocal of the speed. "0.000000000073 minutes" is one every 13.7 billion minutes, or ~26,000 years. Thanks! 172.70.46.107 20:20, 5 February 2025 (UTC)

Me again. Should the column header "revolution time" be "rotation time"? In every instance, the axis of motion is within the object itself; even the second/minute/hour hands go around the axis. 141.101.76.73 16:41, 6 February 2025 (UTC)

TRIVIA 16 2/3 RPM phonographs were used for some voice-recorings back in the day. 172.68.26.24 21:01, 5 February 2025 (UTC)

My parent's old record player (60's, probably) had 4 possible speeds: 16, 33, 45, 78. By the early 80's the current ones only had 33 and 45. Rps (talk) 16:59, 7 February 2025 (UTC)

Album goes back to stacks of 78s. A symphony or opera would be 2, 3, 4 or more disks. They were bound like a photo-album with a leaf for each disk. "78" wasn't "standardized" until the format was fading. 3600-rpm motor and 46-tooth gear is incomplete (one tooth gear??) Early discs were from 60 to 130 rpm. Users would adjust speed by ear (also to ease pitch-matching for karaoke). Only as LPs arrived did someone invent the number "78.26 rpm" (no recordplayer and few lathes of the period were near that accurate). --PRR (talk) 02:34, 6 February 2025 (UTC)

Indeed, my parents had a large collection of old records and at least one had a speed marking of 80rpm.--172.68.186.43 09:17, 6 February 2025 (UTC)

With wind-up players, a lot of them started off playing at one speed and ended playing at a completely different one anyway...172.68.186.50 09:43, 6 February 2025 (UTC)

I suspect there's not many consumers needing a Uranium Enrichment Centrifuge... at least outside of a few countries in the Middle East. --172.70.58.6 08:50, 6 February 2025 (UTC)

Might face some regulatory / export license issues too.172.70.86.129 11:34, 6 February 2025 (UTC)

I feel like there was a lost opportunity to have Dr. Who's Sonic Screwdriver on the list. Maybe the rpms are unknown.162.158.159.107 13:05, 6 February 2025 (UTC)

The table says that 0.00070 "seems off; a sidereal day is 23.93 hours". That's just because (like all of the other settings) 0.00070 is quoted with only 2 significant digits. Every period between 23.64 and 23.98 hours would round to 0.00070 RPM. 162.158.134.199 13:58, 6 February 2025 (UTC)

The question I have is: why are dental drill speeds so high? 172.70.247.92 17:21, 6 February 2025 (UTC)

"why are dental drill speeds so high?" It hurts less. (Are you old enough to remember routine use of belt-driven dental drills?) You can cut a given amount of material (wood, steel, tooth) quickly with heavy force or high speed. Neither is really fun, but hi-speed is generally preferred. --PRR (talk) 19:08, 6 February 2025 (UTC)

Although some materials behave badly to heat (either work-hardening, for some alloys, or melting/burning, like plastics) and that's why variable-speed hand-drills/etc usefully have low speeds (for essentially the same force, when that's done via reostat rather than an actual gearbox). On the few occasions I've had my teeth drilled, I'm pretty sure I've detected the pungent smell of fried tooth-fragments, but it was nothing like as strong as smelling my own nose-flesh being burnt one of the times I had it cauterised to try (and fail) to prevent excessive nosebleeds. 172.69.79.139 21:15, 6 February 2025 (UTC)

The latest NMR CPMAS probes send their rotors to go at 9.6 Mrpm, M=mega. [1] --172.69.109.172 21:56, 7 February 2025 (UTC)

Should we list the rotor diameters to achieve the mach 8 speed mentioned in the title text in the table? I don't think that we should. guess who (if you desire conversing | what i have done) 06:01, 24 February 2025 (UTC)

I (obviously since I worked it all out) think it is in the spirit of the ridiculous idea of the comic and XKCD generally to do these calculations. That said, I'm getting different numbers than your update to make it Mach 8. Denver87 (talk) 16:21, 24 February 2025 (UTC)

I get the following: 4,799au, 74,866km, 37,733km, 3,144km, 52.4km, 1,588m, 1,165m, 728m, 175m, 34.9m, 21.0m, 149.7cm, 87.3cm, 174.7mm. Denver87 (talk) 16:21, 24 February 2025 (UTC)

Happy to share calculation notes, but here's the example for the dental drill: 300,000rpm = 5,000 rps; diameter of: 174.7mm --> circumference of: pi * 174.7mm = 548.8mm; 548.8mm * 5000rps = 2,744,000mm/sec = 2744m/sec; Mach 8 = 8 * 343m/sec = 2744m/sec. Denver87 (talk) 16:21, 24 February 2025 (UTC)

If you agree with the calculations, one of us can at least update it. Denver87 (talk) 16:21, 24 February 2025 (UTC)
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