526: Converting to Metric
|Converting to Metric|
Title text: According to River, "adequate" vacuuming systems drain the human body at about half a liter per second.
Most people will eventually develop an intuitive feel for how big certain measurements are (e.g., how long an inch or a foot is, how much a pound weighs). This comic points out that people who were brought up using the United States system of customary units probably don't have the same intuitive understanding for metric units and attempts to provide some benchmarks for these people. Most of the benchmarks are common sense, highly-useful ones (e.g., if it's 30 degrees Celsius, you'd be quite comfortable outside dressed for the beach) but some of the benchmarks are humorous and/or completely useless as can be seen below.
In the book Thing Explainer a similar chart for metrics is shown in the explanation for How to count things, with four of the five measures from this comic also explained in simple language. Only volume is left out there. Only thing used in both explanations is the weight of a cat, but in the book it weighs 5 kg rather than 4 kg in this comic.
- 60 °C - Earth's hottest: The hottest temperature recorded on earth is actually "only" 56.7 °C. There have been reports of temperatures ten-twenty degrees higher (70−80 °C) but these measurements are not verified or accepted as world records.
- 45 °C, 40 °C, 35 °C: Various heat waves. Dubai is a city in the United Arab Emirates, and is smack-dab in the middle of an equatorial desert, so their heat waves can get hot!. The southern United States will typically be a few degrees hotter than the northern United States simply because it's closer to the equator, but as mentioned they're both above "Beach Weather".
- 30 °C: A little too hot so perfect for a trip to the beach.
- 25 °C: Would as mentioned be too warm for room temperature...
- 20 °C: Defined as room temperature in many experimental settings. For some this would feel a little cool.
- 10 °C: Definitely wear a jacket. Especially if there is just a little breeze.
- 0 °C: The freezing point of water.
- −5 °C, −10 °C: In Moscow −10 °C is not really that cold - it can go "spit goes clink" cold in Moscow, whereas −5 °C in Boston may be very cold.
- −20 °C - FuckFuckFuckCold, −30 °C - Fuuuuuuuuuuck!: This is implied to be basically what some people would say when they step outside at this temperature. In reality, it would be best to keep ones's mouth firmly closed. At −30 °C, without taking wind chill into account, exposed skin will feel painful in under a minute and frostbite could begin in as little as ten minutes . The differing statements seem to imply that at −20 °C, the user would be saying "fuck" repeatedly, whereas at −30 °C, the user is incapable of closing their mouth after starting the first "fuck", and so extends it into one long one.
- −40 °C - Spit goes "clink": As shown in the drawing your spit would freeze before it hits the ground. This is the agreement point of the two temperature scales i.e. −40 °C = −40 °F.
See also 1643: Degrees about not being able to choose between the two temperature scales.
- 1 cm - Width of microSD card, 3 cm - Length of SD card: Refers to the memory cards used in cell phones, digital cameras, etc.
- 12 cm: CD-ROM is a common object so nice to know it is a dozen centimeters.
- 14 cm: Most males would probably exaggerate the size of their penis, but 14–15 cm is very average.
- 15 cm: A Bic pen.
- 80 cm: A typical doorway is also of standard size. This is barely over the minimum size typically required by codes for buildings (30 inches or 76.2 cm in US), but more than 50% over the size required for aircraft emergency exits. (It may seem illogical that larger doors are required in buildings than in airplanes, given airplanes are arguably more dangerous. However, there is no real disadvantage to using larger doors in buildings, which are not significantly pressurized, but using larger doors in aircraft would increase the force on the door caused by cabin pressure proportionally.)
- 1 m - Lightsaber blade: Refers to the weapon used in the Star Wars movie franchise. Canonically, the length of a lightsaber's blade varies greatly depending on the setting of the weapon, but "one meter" is by no means a bad approximation.
- 170 cm - Summer Glau: Refers to the height of the actress who portrays the character River Tam on the TV show Firefly.
- 200 cm - Darth Vader: Refers to the height of the main antagonist from Star Wars.
- 2.5 m: A ceiling - of course very much depending on which type of building you are in!
- 5 m: A car length - also very much depending on the car...
- 16 m 4 cm - Human tower of Serenity crew: Again, this refers to the Firefly TV show, which takes place mostly on a space ship called Serenity.
- Presumably, if all the crew of Serenity were stacked on top of each other, this would be their combined height.
- The comic depicts four characters from the show standing on top of each other; the bottom figure is the crew's captain, Malcolm Reynolds in his signature coat. Judging from the other drawing of Summer Glau from the volume section, she is standing on top of the captain.
- The other five members of the crew should also be stacked on top of these four to reach the 16.04 m height - giving them an average height of 1.78 m (8 cm more than Summer Glau's height!)
- Here both the SI unit m/s as well as the more commonly used unit kph (km/h) is given. Note that the SI prefers "km/h" over the non-standard abbreviation "kph".
- 5 kph - 1.5 m/s: Walking at a normal pace.
- 13−25 kph - 3.5−7 m/s: Jogging to sprinting.
- 35 kph - 10 m/s - Fastest human: As of 2009, the fastest a human has been recorded to run in a single sprint is actually 12.4 m/s or 44.7 km/h, a record set by Usain Bolt.
- 45−55 kph - 13−15 m/s: Both cats and rabbits go much faster than normal people.
- 75 kph - 20 m/s - Raptor: It's a comic written by Randall, of course a reference to the velociraptors from Jurassic Park was going to be here.
- 100 kph - 25 m/s: A slow highway. (25m/s actually exactly equals 90kph.)
- 110 kph - 30 m/s - Interstate (65 mph): Refers to the American highway system. (65 mph would actually be only 104.6 km/h.)
- 120 kph - 35 m/s - Speed you actually go when it says "65": People routinely break the aforementioned speed limit, and the police typically don't mind as long as it's not posing any danger.
- 140 kph - 40 m/s - Raptor on hoverboard: The hoverboard and its speed (~88 mph) is probably a reference to the Back to the Future Part II, though hoverboards are a fairly common trope in older science fiction stories. Randall obviously did a lot of google searching on this subject the week before - see 522: Google Trends.
- 3 mL: The amount of blood in a fieldmouse. A similar amount is used in comic 434: xkcd Goes to the Airport.
- 5 mL: A teaspoon - a very common measure.
- 30 mL - Nasal passages, 40 mL - Shot glass: The comic points out that you could just about fill a shot glass using the mucus from your nose. Since shot glasses are usually used for mixed drinks, the comic jokes that this mucus could constitute a new, disgusting drink - and this is depicted in the drawing.
- 350 mL: Soda can (this is roughly correct for the cans used in the U.S., which hold 12 fluid ounces or 355 mL; in Europe, soda cans commonly hold 330 mL or 500 mL).
- 500 mL: Water bottle (this is also the volume of a European water bottle).
- 3 L - Two-liter bottle: Refers to a bottle which contains 2 L (in the US usually soda). There is debate as to the reason for the discrepancy in volume. It may be a reference to stereotypical Americans consuming a lot of high-calorie foods and drinks. The simpler explanation would be that it is a joke. The two-liter bottle is named using its volume. Labeling it with a volume of three liters is the joke.
- 5 L: An adult male has about 5 L of blood in his body (An adequate vacuuming system could drain this blood out in 10 s - as per the title text!)
- 30 L - Milk crate: Refers to a type of small box originally used to transport milk but now often in demand to be used as bicycle basket, storage spaces, etc.
- 55 L - Summer Glau: Again, this refers to the actress from Firefly.
- 65 L - Dennis Kucinich: An American politician belonging to the Democratic party, noted for his relatively strong (for the US) leftist views.
- 75 L - Ron Paul: An American politician belonging to the rival Republican party, noted for his strong rightist views.
- 200 L: Volume of a refrigerator.
- As shown in the drawing of this part of the comic, the three persons mentioned above - Glau, Kucinich and Paul (summing up to 195 L) - could in principle all fit inside a standard refrigerator. Cueball thus attempts to push them all inside of one - though human bodies are not likely to be sufficiently malleable for this to succeed.
- 3 g - Peanut M&M: A small chocolate candy with a peanut inside.
- 100 g - Cell phone: The weight of a cell phone very much depends on the age, type etc.
- 500 g: A bottle of water contains 500 mL according to the volume section and thus has a mass of 500 g.
- 1−3 kg: Different types of laptops. The newest and the best is the lightest...
- 5 kg - LCD monitor: A modern flat-screen-style monitor.
- 15 kg - CRT monitor: An older-style, cathode ray tube-based monitor.
- This ends the section on computer screens, which overrode the normal sequence by weight as the next two feline inspired entries are lighter than the two before. This was presumably done so that the reader's eye will be confused or amused at seeing (in the comic's caseless captioning font) CRT immediately followed by CAT in the vertical text column.
- 4 kg - Cat, 4.1 kg - Cat (with caption): Refers to the internet's love of putting captions on cats. Usually, this is done in a graphics program, but here the cat is actually physically carrying around his caption. The "with caption" part is most likely a reference to 262: IN UR REALITY, where Black Hat glues captions to cats, after running out of staples.
- 60 kg - Lady: For instance if she is Summer Glau - could be her again depicted in the comic - the average weight of an adult woman.
- 70 kg - Dude: Here depicted as Cueball who is the average guy, and 70 kg is average weight for an adult man.
- 150 kg - Shaq: Shaquille O'Neal, a famously tall basketball player.
- 200 kg - Your mom,
- 220 kg - Your mom (incl. cheap jewelry),
- 223 kg - Your mom (also incl. makeup)
- The last three refer to a common type of Your mom joking insult whereby someone insults someone else's mother in a creative way. Here, the comic slyly calls your mom fat, then implies she wears way too much jewelry and finally also 3 kg of makeup. This is a common theme in xkcd. (20 kg of "cheap" jewelry has several times the volume than 20 kg of gold jewelry, because of the difference in density.)
 Title text
The title text refers once again to Summer Glau's Firefly character, River Tam, who (after being subjected to a long series of medical experiments) is severely mentally ill and often comes out with macabre — though scientifically accurate — pronouncements. In Firefly episode "Safe" (season 1, episode 7), she says: "The human body can be drained of blood in 8.6 seconds given adequate vacuuming systems."
 Conversion table
The idea of the comic is to establish new metric reference points and not to resort to unit conversions. Nevertheless, the following table lists all units from the comic with their US customary equivalents:
|60 °C||140 °F||1 cm||0.4 in||km/h||mph||m/s||3 mL||0.10 fl oz||3 g||0.11 oz|
|45 °C||113 °F||3 cm||1.2 in||5||3||1.5||5 mL||0.17 fl oz||100 g||3.5 oz|
|40 °C||104 F||12 cm||4.7 in||13||8||3.5||30 mL||1.0 fl oz||500 g||1.1 lb|
|35 °C||95 °F||14 cm||5.5 in||25||16||7||40 mL||1.4 fl oz||1 kg||2.2 lb|
|30 °C||86 °F||15 cm||5.9 in||35||22||10||350 mL||12 fl oz||2 kg||4.4 lb|
|25 °C||77 °F||80 cm||31 in||45||28||13||500 mL||17 fl oz||3 kg||6.6 lb|
|20 °C||68 °F||1 m||3 ft 3 in||55||34||15||3 L||0.8 gal||5 kg||11 lb|
|10 °C||50 °F||170 cm||5 ft 7 in||75||47||20||5 L||1.3 gal||15 kg||33 lb|
|0 °C||32 °F||200 cm||6 ft 7 in||100||62||25||30 L||7.9 gal||4 kg||8.8 lb|
|-5 °C||23 °F||2.5 m||8 ft 2 in||110||68||30||55 L||15 gal||4.1 kg||9.0 lb|
|-10 °C||14 °F||5 m||16 ft||120||75||35||65 L||17 gal||60 kg||130 lb|
|-20 °C||-4 °F||16.04 m||52 ft 7 in||140||87||40||75 L||20 gal||70 kg||150 lb|
|-30 °C||-22 °F||200 L||53 gal||150 kg||330 lb|
|-40 °C||-40 °F||200 kg||440 lb|
|220 kg||485 lb|
|223 kg||492 lb|
- Guide to Converting to Metric
- [There are five frames with tables for different units. Between the two upper frames is the following text:]
- The key to converting to metric is establishing
- new reference points. When you hear "26°C",
- instead of thinking "That's 79°F" you should think,
- "that's warmer than a house but cool for swimming."
- Here are some helpful tables of reference points:
- [The frame to the left of the above text:]
60°C Earth's hottest 45°C Dubai heat wave 40°C Southern US heat wave 35°C Northern US heat wave 30°C Beach weather 25°C Warm room 20°C Room temperature 10°C Jacket weather 0°C Snow! -5°C Cold day (Boston) -10°C Cold day (Moscow) -20°C Fuckfuckfuckcold -30°C Fuuuuuuuuuuck! -40°C Spit goes "clink"
- [Next to the last three entries we see Cueball spitting on the ground. The spit bounces.]
- Cueball: Ptoo
- Spit: Clink!
- [The frame to the right of the above text:]
1 cm Width of microSD card 3 cm Length of SD card 12 cm CD diameter 14 cm Penis 15 cm BIC pen 80 cm Doorway width 1 m Lightsaber blade 170 cm Summer Glau 200 cm Darth Vader 2.5 m Ceiling 5 m Car-length 16 m 4 cm Human tower of Serenity crew
- [To the right of the table is a human tower of four of the people from the Serenity crew. The head of the upper person is right below the first entry.]
- [The frame below to the left:]
kph m/s 5 1.5 Walking 13 3.5 Jogging 25 7 Sprinting 35 10 Fastest human 45 13 Housecat 55 15 Rabbit 75 20 Raptor 100 25 Slow highway 110 30 Interstate (65 mph) 120 35 Speed you actually go when it says “65” 140 40 Raptor on hoverboard
- [The frame below in the middle:]
3 mL Blood in a fieldmouse 5 mL Teaspoon 30 mL Nasal passages 40 mL Shot glass 350 mL Soda can 500 mL Water bottle 3 L Two-liter bottle 5 L Blood in a human male 30 L Milk crate 55 L Summer Glau 65 L Dennis Kucinich 75 L Ron Paul 200 L Fridge
- [Next to the entry on nasal passages and shoot glass (starting one entry higher and finishing one entry lower) are the following text:]
- So, when it's blocked
- the mucus in your
- nose could about
- fill a shot glass.
- [Below this text is a drawing of a mucus filled shot glass.]
- Related: I've
- invented the
- worst mixed
- drink ever.
- [Below this next to the four last entries we see Cueball shoving Summer Glau, Dennis Kucinich and Ron Paul into an open fridge. Above the fridge in a loosely drawn ellipse are the following text:]
- [The frame below to the right:]
3 g Peanut M&M 100 g Cell phone 500 g Bottled water 1 kg Ultraportable laptop 2 kg Light-medium laptop 3 kg Heavy laptop 5 kg LCD monitor 15 kg CRT monitor 4 kg Cat 4.1 kg Cat (with caption) 60 kg Lady 70 kg Dude 150 kg Shaq 200 kg Your mom 220 kg Your mom (incl. cheap jewelry) 223 kg Your mom (also incl. makeup)
- [Next to the entries of cat and cat (with caption) are two drawings of cats. The second one has a caption across its chest.]
- Cat (with caption): Mrowl?
- [Below this and next to the lady and dude entries (and the Shaq entry) are drawings of Megan and Cueball.]
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