explain xkcd - User contributions [en]

Talk:1474: Screws

2015-01-17T07:21:48Z

199.27.133.137:

This page is now on the first page of google for "uranium screw". [[User:Mrmakeit|Mrmakeit]] ([[User talk:Mrmakeit|talk]]) 05:31, 16 January 2015 (UTC)
:And as of now, this page is the #1 result for "uranium screw". The second is the xkcd fora thread on this comic, and the third is our home page. [[User:NealCruco|NealCruco]] ([[User talk:NealCruco|talk]]) 16:47, 16 January 2015 (UTC)

I don't think that patent is the right one, it seems to describe a uranium decontamination procedure, not a screw made of uranium like in the comic. [[User:LeoDeQuirm|LeoDeQuirm]] ([[User talk:LeoDeQuirm|talk]]) 05:46, 16 January 2015 (UTC)

I'm pretty sure the "uranium screw" is just a reference to the fact that the head of the screw appears to have split in two ("fissioned"), as opposed to a normal flat head screw that still has the edges connected. [[User:Sam887|Sam887]] ([[User talk:Sam887|talk]]) 05:50, 16 January 2015 (UTC)

Just a shot in the dark here, but a company that sells uranium ore and radiological equipment happens to also sell screws for one of its Geigers that look just like the screw cross-section in the comic. [http://www.uraniumrocks.com/products/replacement-circuit-board-mount-screws-for-victoreen-cdv-700-short] [[User:Conqu2|Conqu2]] ([[User talk:Conqu2|talk]]) 06:01, 16 January 2015 (UTC)

I was wondering if the "uranium screw" was referring to the Demon Core -- two hemispherical domes that Louis Slotin was holding apart with a screwdriver. Then I remembered the Demon Core was plutonium, not uranium. [[Special:Contributions/173.245.48.119|173.245.48.119]] 06:49, 16 January 2015 (UTC)

There are ferrous alloys containing (depleted, of course ;-) uranium for "increase[d] toughness and strength". [http://en.wikipedia.org/wiki/Ferrouranium] [[User:Knob creek|Knob creek]] ([[User talk:Knob creek|talk]]) 09:21, 16 January 2015 (UTC)

I think the be was going for apple's pentalobe screw with the 5 pointed star {{unsigned ip|108.162.238.162}}

I don't think the uranium screws are named for their use in stuff to do with uranium, as I have both seen and used screws that look like that before. It's basically a flat head screw whose divot extends all the way across the face of the screw. I agree more with the previous commentor who notes that the screw looks like it has fissioned. [[Special:Contributions/108.162.237.182|108.162.237.182]] 06:34, 16 January 2015 (UTC)

An actual rivet is neither a screw nor a bolt; it's a fastener that is placed and then has one end plastically deformed -- traditionally by a rivet gun, but more often in smaller sizes by some sort of press or clamp. (Pop rivets are hollow, and are deformed by pulling a cone-sheaped wedge into the open end of the hollow core.) There's no way to remove one except to destroy it (drill it out or cut one end off). The item pictured could also be the head of a carriage bolt, but that's no help if you can't get at the other end of the bolt. Randall is slightly pessemistic, though: there *are* some "security" screws and bolts that use a slightly-elliptical domed head that's hard to tell from a rivet; they can be unscrewed, but only with a matching slightly-elliptical socket. [[Special:Contributions/199.27.133.70|199.27.133.70]] 06:35, 16 January 2015 (UTC)

All of which can be removed by a sonic screwdriver. Totally a real thing. {{unsigned ip|173.245.50.86}}

Could the "cursed -1" be a Nethack reference? I don't know if Dungeons and Dragons has the "blessed/uncursed/cursed" status, but in Nethack cursed items with negative enchantments (denoted "cursed -whatever") are a pretty common occurrence. [[Special:Contributions/199.27.133.25|199.27.133.25]] 07:31, 16 January 2015 (UTC)

In Nethack, Cursed objects cannot be removed. Seems appropriate. At first I thought it was a pozidrive screw head. Posts on the fission screw head: where have you seen screws whose divot does *not* extend across the head? {{unsigned ip|199.27.128.230}}

[[User:Kreuiter|Kreuiter]] ([[User talk:Kreuiter|talk]]) 08:03, 16 January 2015 (UTC)from wikipedia: Louis Philippe Joseph d'Orléans (13 April 1747 – 6 November 1793) commonly known as Philippe, was a member of a cadet branch of the House of Bourbon, the ruling dynasty of France. He actively supported the French Revolution and adopted the name Philippe Égalité, but was nonetheless guillotined during the Reign of Terror

I don't think it is specifically a reference to Nethack as a lot of ol games (both video and tabletop) use the mechanic of non removable cursed objects. It is common enough in my opinion that we could argue about until we are blue in the face and get nowhere. {{unsigned ip|108.162.237.193}}

uranium screw may be a reference to [http://en.wikipedia.org/wiki/Louis_Slotin#Criticality_accident Louis Slotin], who died when he was using a screw driver to seperate two halves of a plutonium sphere as part of a science demonstration, and triggered a large burst of radiation when his hand slipped.
--[[Special:Contributions/108.162.216.59|108.162.216.59]] 08:28, 16 January 2015 (UTC)

I'm thinking it might benefit the article to include a place in the wikitable for the correct term for each drive socket. Of course their are not correct terms for each of them. Not to mention rivets and Phillip's heads don't even have drive sockets. [[Special:Contributions/173.245.56.189|173.245.56.189]] 09:04, 16 January 2015 (UTC)BLuDgeons

If you suggest cursed-1 is because if misuse - I in first place thought of [http://en.wikipedia.org/wiki/List_of_screw_drives#Pozidriv] as the cursed one - because Philipps and Pozidriv are slightly incompatible and causes damage. [[Special:Contributions/108.162.254.18|108.162.254.18]] 09:09, 16 January 2015 (UTC)

:+1, the cursed one looked to me like pozidriv at the first glance, and it's really cursed as interchanging them leads to damage ... And the most fun is when you get some Chinese crap that looks like pozidriv but it doesn't fit so you use philips which doesn't quite fit too but at least it can be inserted and you end up damaging both the driver and the screw :-/ --kavol, [[Special:Contributions/108.162.254.96|108.162.254.96]] 10:02, 16 January 2015 (UTC)

Is it really true that Phillips head are 'commonly used in construction'? At least in Europe they were replaced by Pozidriv in the 1990's and these days by Torx. {{unsigned|Popup}}
:As a former (late 2000s to 2012, pre-college) construction worker in California, Texas, and Oklahoma, yes. Philips are very common in construction here. [[Special:Contributions/108.162.221.243|108.162.221.243]] 06:08, 17 January 2015 (UTC)

Maybe this depends on the quality of the product? If i look around, i find lots of products held together by phillips screws and only a few (usually more hi-tech and expensive) one with torx screws. [[User:Knob creek|Knob creek]] ([[User talk:Knob creek|talk]]) 09:28, 16 January 2015 (UTC)

:er, what do you call "a product"? - If "construction" is mentioned, I imagine things like wooden skeleton of a roof, fastening of windows/doors, self-tapping screws, wallplug screws ... and it's almost 100% pozidriv and torx here in central Europe. ("Almost" accounts for imports by non-european companies.) If I imagine metal constructions, from racks to bridges, hex and inbus (= hex slot) prevail. --kavol, [[Special:Contributions/108.162.254.96|108.162.254.96]] 10:02, 16 January 2015 (UTC)

:: Granted I'm not in the construction trade, and I'm in UK rather than continental Europe, but I have never seen Torx used in construction. In my experience, the majority is Pozi, and the rest is Phillips. --[[User:Pudder|Pudder]] ([[User talk:Pudder|talk]]) 13:06, 16 January 2015 (UTC)

Perhaps a reference to http://xkcd.com/927/ - Standards? [[Special:Contributions/141.101.79.61|141.101.79.61]]

Phillips screws have a larger number for larger size, not smaller. {{unsigned ip|108.162.216.35}}

I'm surprised Randall didn't include square/Robertson screws/drivers. Just as bad as hex-recess, but when you actually USE them they are great! Combination Robertson-Phillips are good too but rarer. And do NOT get me started about the untold types of tamper-proof designs... --BigMal // [[Special:Contributions/108.162.216.209|108.162.216.209]] 13:06, 16 January 2015 (UTC)
:The most awkward, I find, are star-shaped (5/6-pointer) screws with a central 'post' that requires a hole-ended screwdriver-bit of the appropriate shape to be used (may also aid in positive positioning of the tool, but not much more than normally so SFAICT it's just there to be awkward without the right tools by manufacturer-mandated professionals). Luckily, I've ''got'' screwdriver-heads for just about every conceivable 'uncursed' screwhead (48 different types and sizes in one handy kit alone, not even counting socket-heads and 'cursed' screw drilling-outers). Especially good for laptop repair, to get around deliberately proprietry systems with small and (deliberately) akward screws; as opposed to bicycle repair, which I'm sure is usually for the stated practical torque reasons. [[Special:Contributions/141.101.98.247|141.101.98.247]] 13:59, 16 January 2015 (UTC)

"cursed -1 <something>" is definitely a standard NetHack item description format, but it applies to D&D too. In general, "cursed" means you cannot remove the item, and the number is describing the item's effectiveness compared to a standard (+0) version of the item. In this case, both can be appropriate: "cursed" because -as noted- you cannot remove it in the normal way. "-1" probably comes from being unable to tighten the screw far enough to fully satisfy its purpose: maybe the joint is slightly loose, or the head of the screw is left slightly protruding, so that it easily catches on other things.
[[Special:Contributions/141.101.80.80|141.101.80.80]] 13:28, 16 January 2015 (UTC)

Rather than two (still) separate fissile hemispheres, that 'gap' is obviously a continuation of material around the back of a schematic cross-section of a whole sphere with a core currently missing. I think the fissile plug will be inserted/fired at the required juncture to fill this, from the side. Very like the device in the film The Fifth Protocol, for easy cinematic reference of the concept. (Noting that 'gun-type' nuclear devices tend to fire the 'enclosing' larger subcritical mass, spheroidal or cylindrical ''onto'' the smaller and fixed 'plug' to fill the gap between it and the surrounding neutron reflector jacket. For several very good reasons. Thus that sphere would be shoved onto the currently missing 'core', although it makes the reflector assembly and positioning a bit more complex as well, compared with a cylindrical sleeve.) [[Special:Contributions/141.101.98.247|141.101.98.247]] 13:49, 16 January 2015 (UTC)

The Cursed -1 Phillips Head is much more likely to be a [http://en.wikipedia.org/wiki/List_of_screw_drives#Pozidriv Pozidriv] head than a worn Philips head. The cursed -1 implication if used with a Philips driver is certainly deserved. [[Special:Contributions/141.101.106.101|141.101.106.101]] 14:59, 16 January 2015 (UTC)

Re: Uranium Screw... see http://www.google.com/patents/US20060088457{{unsigned ip|108.162.219.97}}

Uranium screws were used in the assembly of the Fat Man nuclear bomb. All parts of the tamper were made with natural uranium, including the screws and hinges:
http://blog.nuclearsecrecy.com/2014/11/10/fat-mans-uranium/
[[User:Rocbolt|Rocbolt]] ([[User talk:Rocbolt|talk]]) 15:34, 16 January 2015 (UTC)rocbolt

[[User:Rocbolt]] has it right. It's not a metaphor or a joke. https://www.google.com/search?q=%22uranium%20screws%22%20%2dxkcd [[User:Pesthouse|Pesthouse]] ([[User talk:Pesthouse|talk]]) 15:41, 16 January 2015 (UTC)

Did anyone notice that the "shortcut icon" of the page was changed together with this comic? Its sort of blurred: http://i.imgur.com/ArEbL5r.jpg?1 compared to the original image http://xkcd.com/s/919f27.ico {{unsigned ip|141.101.80.4}}

Possibly a reference to Apple's iPhone "tamper-resistant" screws http://en.wikipedia.org/wiki/Pentalobe_screw [[Special:Contributions/188.114.98.252|188.114.98.252]] 17:38, 16 January 2015 (UTC)

Screws made of uranium were used to hold the tamper plug of the fissile core of the Trinity nuclear device together. I think that's what "Uranium Screw" refers to, and why the screw is radiating: it is radioactive. [[User:Arnold Chiari II|Arnold Chiari II]] ([[User talk:Arnold Chiari II|talk]]) 15:35, 16 January 2015 (UTC)

Not sure why the page says depleted Uranium. I think they were natural uranium, which is radioactive. Rocbolt's reference supports this [[User:Arnold Chiari II|Arnold Chiari II]] ([[User talk:Arnold Chiari II|talk]]) 21:26, 16 January 2015 (UTC)

Depleted uranium is nearly pure U-238, which '''is''' radioactive, but has a half-life 6X longer than U-235.

Technically, a rivet '''is''' a bolt, but the usage of ''bolt'' to refer to a non-threaded object with a head is archaic.

I have seen a few objects that look like "flat head", where the slot doesn't extend all the way out to the edge, but precious few, compared to the fairly common "standard" woodscrew, where the slot goes all the way to the edge, as shown at "uranium screw".

I thought "Cursed -1" was a clever double reference to the common RPG meme and to what happens after someone has confounded Philips, Pozidriv, or Reed and Prince with one of the others and the fireworks from using a tool designed for one on a screw of another type.--[[Special:Contributions/199.27.128.197|199.27.128.197]] 00:32, 17 January 2015 (UTC)

Could the Amazon one be a reference to star ratings? --[[Special:Contributions/108.162.221.167|108.162.221.167]] 01:58, 17 January 2015 (UTC)

The rivet could also be a nail. While a nail isn't a screw, neither is a rivet. [[User:Glen442|Glen442]] ([[User talk:Glen442|talk]]) 03:20, 17 January 2015 (UTC)

I think the bit about "Phillip's Head" is an obvious note about the frustration of dealing with different screw types -- as in "I'm so frustrated dealing with all these screw types I'm going to find the inventor of the Phillips head screw and chop his head off!"

1474: Screws

2015-01-17T07:20:23Z

199.27.133.137: Undo revision 82918 by 199.27.133.137 (talk)

{{comic
| number = 1474
| date = January 16, 2015
| title = Screws
| image = screws.png
| titletext = If you encounter a hex bolt, but you only brought screwdrivers, you can try sandwiching the head of the bolt between two parallel screwdriver shafts, squeezing the screwdrivers together with a hand at either end, then twisting. It doesn't work and it's a great way to hurt yourself, but you can try it!
}}

==Explanation==
{{incomplete|May still needs expansion, possibly with origins of the various real screws?}}

The comic features various real or imagined types of screws, listed below.

{| class="wikitable"
! style="width: 25%"|Screw type
! Description
|-
| Phillips head
| {{w|List of screw drives#Phillips|Phillips screw drive}} and its corresponding screw head is one of the most recognizable types of screw heads that is commonly used in construction. This type of screw head was named after its inventor, a US businessman {{w|Henry F. Phillips}}. Neither the inventor nor his invention have any relationship to the Dutch electronics manufacturing company with similar, but not exactly the same name {{w|Philips}}.
|-
| Flat head
| {{w|List_of_screw_drives#Slot|Slot head screws}} are frequently erroneously referred to as flat heads (a flat head screw refers, in fact, to the shape of the screw head, regardless of the shape of the drive socket). The slot head is also commonly used in construction. The diagram shows the slot truncated, while typically the slot almost always runs across the entire head of the screw (as in the case of the "uranium screw" below).
|-
| Uh oh. Maybe it's on Amazon? (star-shaped screw)
| Manufacturers sometimes use screws that require special screwdrivers in order to prevent the customer from opening the product. The reference to Amazon is the speaker's suggestion to look on Amazon.com for the appropriate screwdriver. A number of star-shaped screw heads exist, notably the six-pointed {{w|Torx}}, and Apple's rounded {{w|Pentalobe screw|pentalobe screw}}, although there is no popular design that uses the 5-pointed star shape depicted in the comic. Torx screws are common in automotive applications — they are easier to tighten with electric screwdrivers — and on bicycles where a higher tightening torque is needed than hex screws can support. They are also commonly used on disk brake mounts.

|-
| Cursed -1 Phillips head
| The head of a screw can be stripped by overuse, tightening the screw too much, using the wrong size screwdriver, or other misuse. As the driving surfaces wear away, removing the screw becomes more difficult, and the added pressure needed to drive the screw usually damages it further.

The addition of "cursed" and "-1" in the titles is a reference to various fantasy games (e.g. Dungeons and Dragons), where magical "cursed" items appear frequently. This often makes the cursed equipment (in the case of armor or weapons) incredibly difficult to remove, as it will cling to the wielder. Similarly, the cursed Phillips Head screw becomes difficult to remove due to the stripped head.

The "-1" refers to the damage of the screw head. In fantasy games, items such as weapons and armor may have an "enchantment", with a positive enchantment making the item more effective, and a negative enchantment making the item less effective. Negatively enchanted items are often also cursed, as is the case with this screw head. The "-1" does not appear to be a reference to a Philips bit-size number, as those are always positive.

Notably, the stripped screw bears a resemblance to a {{w|List_of_screw_drives#Pozidriv|Pozidriv head}}, a modified version of the Phillips head designed to resist slipping and subsequent stripping.
|-
| Rivet
| A {{w|rivet}} is not a screw - it is a permanent fastener which is secured by deforming the body of the fastener. Rivets cannot be removed with a screwdriver, they must be "drilled out". Some bolts also have rounded rivet-style heads, though, with no means of gripping them.
|-
| Phillips head ruiner ''(actually a hex screw)''
| A reference to the fact that {{w|List_of_screw_drives#Hex_socket|hex socket}} screws can, in a pinch, be removed with a Phillips screwdriver (rather than the intended {{w|Allen wrench}}) but this will likely damage the screwdriver in the process. Hex screws are common on bicycles, where they always come in the metric varieties. The same holds for hex screws which ship with Ikea furniture —who bundle a low-quality hex driver for those people who lack them. Imperial-sized hex screws do sometimes surface, to the dissatisfaction of anyone who owns a hex driver set. The smaller hex screws can enter the "-1" state when attempting to unscrew one that has been overtightened —hence the adoption of Torx screws in high-torque applications.

|-
| Uranium screw
| Uranium screws were [http://blog.nuclearsecrecy.com/2014/11/10/fat-mans-uranium/ used] in the [http://www.scintillators.ru/booc/criticality/reports/ref_050.pdf construction] of [http://www.osti.gov/scitech/servlets/purl/769001 nuclear weapons] during the twentieth century. Multiple radially extending short wave-like lines around the screw head symbolize radiant energy output, although real uranium screws were most likely made of depleted uranium, which is [http://www.gulflink.osd.mil/du_ii/du_ii_tabc.htm 40 percent less radioactive] than "raw" naturally-occurring uranium.
|-
| Phillip's head
| This is a literal (and rather morbid) interpretation of the misspelling "Phillip's head" when "Phillips head" is meant. Rather than refer to the screw type, this "screw" is actually a bloody bag containing the severed head of someone named Phillip. It could possibly be an allusion to one of the {{w|Decapitation|decapitations}} of the royal persons that took place several times in the human history, perhaps even more specifically to {{w|French Revolution|revolutionary France}} where {{w|Capital punishment|capital punishment}} by decapitation was made well-known due to introduction of {{w|Guillotine|guillotine}} and its active use against the former royalty. However, despite the {{w|Philip|name Phillip being used by several members of the upper echelon of French royalty}}, none of the {{w|List of people who were beheaded|famous people ever executed this way in France or anywhere else}} were called Phillip, although {{w|Louis Philippe II, Duke of Orléans|Philippe Égalité}}, the adopted name of Louis Philippe Joseph d'Orléans, ''was'' guillotined. Intentionally or otherwise, this last punchline could be described as a "mind screw".
|-
|Hex bolt (title text)
|A {{w|List_of_screw_drives#Hex|hex bolt}} has six external sides, so it could in theory be held by squeezing two screwdriver shafts together with the bolt in between. The amount of force on the two screwdriver shafts needed to turn the hex bolt will probably exceed the strength of human hands - the attempt would most likely only result in causing your hands to cramp or causing the screwdrivers to slip and cause further injury.
|}

==Transcript==
:[Eight drawings of different types of heads each with a caption:]
:Phillips head
:Flat head
:Uh oh. Maybe it's on Amazon?
:Cursed –1 Phillips head
:Crap, it's a ''rivet''.
:Phillips-head ruiner
:Uranium screw (a real thing)
:Phillip's head

{{comic discussion}}

1474: Screws

2015-01-17T07:19:20Z

199.27.133.137: Add note about frustration

{{comic
| number = 1474
| date = January 16, 2015
| title = Screws
| image = screws.png
| titletext = If you encounter a hex bolt, but you only brought screwdrivers, you can try sandwiching the head of the bolt between two parallel screwdriver shafts, squeezing the screwdrivers together with a hand at either end, then twisting. It doesn't work and it's a great way to hurt yourself, but you can try it!
}}

==Explanation==
{{incomplete|May still needs expansion, possibly with origins of the various real screws?}}

The comic features various real or imagined types of screws, listed below.

{| class="wikitable"
! style="width: 25%"|Screw type
! Description
|-
| Phillips head
| {{w|List of screw drives#Phillips|Phillips screw drive}} and its corresponding screw head is one of the most recognizable types of screw heads that is commonly used in construction. This type of screw head was named after its inventor, a US businessman {{w|Henry F. Phillips}}. Neither the inventor nor his invention have any relationship to the Dutch electronics manufacturing company with similar, but not exactly the same name {{w|Philips}}.
|-
| Flat head
| {{w|List_of_screw_drives#Slot|Slot head screws}} are frequently erroneously referred to as flat heads (a flat head screw refers, in fact, to the shape of the screw head, regardless of the shape of the drive socket). The slot head is also commonly used in construction. The diagram shows the slot truncated, while typically the slot almost always runs across the entire head of the screw (as in the case of the "uranium screw" below).
|-
| Uh oh. Maybe it's on Amazon? (star-shaped screw)
| Manufacturers sometimes use screws that require special screwdrivers in order to prevent the customer from opening the product. The reference to Amazon is the speaker's suggestion to look on Amazon.com for the appropriate screwdriver. A number of star-shaped screw heads exist, notably the six-pointed {{w|Torx}}, and Apple's rounded {{w|Pentalobe screw|pentalobe screw}}, although there is no popular design that uses the 5-pointed star shape depicted in the comic. Torx screws are common in automotive applications — they are easier to tighten with electric screwdrivers — and on bicycles where a higher tightening torque is needed than hex screws can support. They are also commonly used on disk brake mounts.

|-
| Cursed -1 Phillips head
| The head of a screw can be stripped by overuse, tightening the screw too much, using the wrong size screwdriver, or other misuse. As the driving surfaces wear away, removing the screw becomes more difficult, and the added pressure needed to drive the screw usually damages it further.

The addition of "cursed" and "-1" in the titles is a reference to various fantasy games (e.g. Dungeons and Dragons), where magical "cursed" items appear frequently. This often makes the cursed equipment (in the case of armor or weapons) incredibly difficult to remove, as it will cling to the wielder. Similarly, the cursed Phillips Head screw becomes difficult to remove due to the stripped head.

The "-1" refers to the damage of the screw head. In fantasy games, items such as weapons and armor may have an "enchantment", with a positive enchantment making the item more effective, and a negative enchantment making the item less effective. Negatively enchanted items are often also cursed, as is the case with this screw head. The "-1" does not appear to be a reference to a Philips bit-size number, as those are always positive.

Notably, the stripped screw bears a resemblance to a {{w|List_of_screw_drives#Pozidriv|Pozidriv head}}, a modified version of the Phillips head designed to resist slipping and subsequent stripping.
|-
| Rivet
| A {{w|rivet}} is not a screw - it is a permanent fastener which is secured by deforming the body of the fastener. Rivets cannot be removed with a screwdriver, they must be "drilled out". Some bolts also have rounded rivet-style heads, though, with no means of gripping them.
|-
| Phillips head ruiner ''(actually a hex screw)''
| A reference to the fact that {{w|List_of_screw_drives#Hex_socket|hex socket}} screws can, in a pinch, be removed with a Phillips screwdriver (rather than the intended {{w|Allen wrench}}) but this will likely damage the screwdriver in the process. Hex screws are common on bicycles, where they always come in the metric varieties. The same holds for hex screws which ship with Ikea furniture —who bundle a low-quality hex driver for those people who lack them. Imperial-sized hex screws do sometimes surface, to the dissatisfaction of anyone who owns a hex driver set. The smaller hex screws can enter the "-1" state when attempting to unscrew one that has been overtightened —hence the adoption of Torx screws in high-torque applications.

|-
| Uranium screw
| Uranium screws were [http://blog.nuclearsecrecy.com/2014/11/10/fat-mans-uranium/ used] in the [http://www.scintillators.ru/booc/criticality/reports/ref_050.pdf construction] of [http://www.osti.gov/scitech/servlets/purl/769001 nuclear weapons] during the twentieth century. Multiple radially extending short wave-like lines around the screw head symbolize radiant energy output, although real uranium screws were most likely made of depleted uranium, which is [http://www.gulflink.osd.mil/du_ii/du_ii_tabc.htm 40 percent less radioactive] than "raw" naturally-occurring uranium.
|-
| Phillip's head
| This is a literal (and rather morbid) interpretation of the misspelling "Phillip's head" when "Phillips head" is meant. Rather than refer to the screw type, this "screw" is actually a bloody bag containing the severed head of someone named Phillip. It could possibly be an allusion to one of the {{w|Decapitation|decapitations}} of the royal persons that took place several times in the human history, perhaps even more specifically to {{w|French Revolution|revolutionary France}} where {{w|Capital punishment|capital punishment}} by decapitation was made well-known due to introduction of {{w|Guillotine|guillotine}} and its active use against the former royalty. However, despite the {{w|Philip|name Phillip being used by several members of the upper echelon of French royalty}}, none of the {{w|List of people who were beheaded|famous people ever executed this way in France or anywhere else}} were called Phillip, although {{w|Louis Philippe II, Duke of Orléans|Philippe Égalité}}, the adopted name of Louis Philippe Joseph d'Orléans, ''was'' guillotined. Intentionally or otherwise, this last punchline could be described as a "mind screw". Also, I think this being at the end to me seems an obvious expression of the frustration of dealing with different screw types as in "this is so frustrating I'm going to find the maker of the Phillips head screw and chop his head off!"
|-
|Hex bolt (title text)
|A {{w|List_of_screw_drives#Hex|hex bolt}} has six external sides, so it could in theory be held by squeezing two screwdriver shafts together with the bolt in between. The amount of force on the two screwdriver shafts needed to turn the hex bolt will probably exceed the strength of human hands - the attempt would most likely only result in causing your hands to cramp or causing the screwdrivers to slip and cause further injury.
|}

==Transcript==
:[Eight drawings of different types of heads each with a caption:]
:Phillips head
:Flat head
:Uh oh. Maybe it's on Amazon?
:Cursed –1 Phillips head
:Crap, it's a ''rivet''.
:Phillips-head ruiner
:Uranium screw (a real thing)
:Phillip's head

{{comic discussion}}

1453: fMRI

2014-11-29T07:55:52Z

199.27.133.137: /* Explanation */ simplify wording

{{comic
| number = 1453
| date = November 28, 2014
| title = fMRI
| image = fmri.png
| titletext = They also showed activation in the parts of the brain associated with exposure to dubious study methodology, concern about unremoved piercings, and exasperation with fMRI techs who won't stop talking about Warped Tour.
}}

==Explanation==
{{w|Functional magnetic resonance imaging|fMRI}} (Functional Magnetic Resonance Imaging), as the name suggests, is an offshoot of the MRI. It shows brain activity, typically while the subject is performing tasks or responding to stimuli. During the test, the subject is laid in a relatively small cylinder inside a big, very loud, machine which produces extremely strong magnetic fields. To prevent damage or injury, the subject must remove all metal objects from their body, including piercings, jewelry, watches etc.

In the tests shown, the brain activity detected is a direct result of the testing environment itself, and has nothing to do with the simple tasks being performed by the subject. During fMRI participants hear loud noises, are confined in a small space (thus the claustrophobia) and have removed their jewelry. The researcher has mistaken these associated brain activities as effects as being caused by ''performing simple memory tasks'' which the participants have been asked to do and not a direct result of the settings of the test. Thus, the brain areas described by Megan are those associated with taking a functional MRI scan, rather than those associated with the "test" supposedly being carried out.

In real experiments, reported activity patterns are always a result of subtracting average brain activity from many samples gathered during task from so called ''resting-state'' activity - which is obtained while subjects are not engaged in any task, thus eliminating the effect the setting has on brain activity. Apparently, the researcher in the comic has failed to account for that in the analysis of the data.

It appears that [[Randall]] makes fun of the overly confident, sweeping statements made by some fMRI researchers, often in the press. In reality the technique requires that the researcher account for several possible sources of errors by, among others, performing proper statistical analyses, multiple comparisons and using proper control groups. These are usually the reasons for {{w|Functional_magnetic_resonance_imaging#Criticism|fMRI criticism}}. See the link for further information, including a famous ironic study of a dead salmon which was shown various pictures of people while fMRI scans were made. The scans could be interpreted as showing meaningful brain activity, until the {{w|multiple comparisons problem}} was properly addressed.

The title text continues directly with this theme by saying that the subjects ''also showed activation in the parts of the brain associated with exposure to dubious study methodology''. It then continues with the jewelry issue, now especially the ''concern about unremoved piercings''. In the worst case these could be ripped off by the strong magnetic field. So it could be of some concern - especially when you take into consideration some of the places people may have piercings that is not obvious to the MRI personnel! The final remark about activation regards ''exasperation with fMRI techs who won't stop talking about Warped Tour''. "{{w|Warped Tour}}" refers to a traveling music festival that has been going since 1995, originally as a punk rock festival, but now with a more diverse set of music. Due to the nature of {{w|Moshing|Mosh Pits}}, the loud, cacophonous music, the facial jewelry of concert-goers and the tight quarters of the pit make it similar in description to an MRI.

==Transcript==
:[Megan talking to an unseen audience in front of an fMRI brain scan]
:Megan: Our fMRI study found that subjects performing simple memory tasks showed activity in the parts of the brain associated with loud noises, claustrophobia, and the removal of jewelry.

{{comic discussion}}
[[Category:Comics with color]]
[[Category:Comics featuring Megan]]

72: Classhole

2014-11-22T18:42:24Z

199.27.133.137: Add references section

{{comic
| number = 72
| date = March 6, 2006
| title = Classhole
| image = classhole.jpg
| titletext = A term coined by my friend Beth
}}

==Explanation==
This subject of this comic is [[Black Hat]] himself. He admits to being an asshole, a profanity that describes someone who does things that antagonize, irritate or anger others (either intentionally or incidentally). While a common example might be someone who weaves in and out of traffic, or someone who parks across two parking spaces, Black Hat is "more creative." This also suggests that, while most people described as assholes are either ignorant or selfish, Black Hat seems to intentionally behave this way strictly to be an asshole, and not for any self-benefit. He claims to be a "classy asshole," or as he coins the {{w|portmanteau}}, a "class-hole." He seems to equate creativity with class, although that seems like a leap. In any event, this is another early Black Hat strip which, for the first time, explicitly sets out that he goes out of his way to wreak havoc.

Among his "pranks," he suggests poking holes in grocery noodle cups. These are pre-packaged cups filled with dried noodles and dried soup mix (either in a separate pouch, or loose in the cup) to which one adds boiling water, which both boils the pasta and dissolves the soup mix to become the soup/broth. By poking holes in the cup, Black Hat ensures that someone pouring boiling water in the cup would have it leak all over them, causing them great surprise and pain.

He also suggests poking holes in condoms, which could cause even more serious consequences. This form of [http://en.wikipedia.org/wiki/Reproductive_coercion#Birth_control_sabotage| contraceptive sabotage] is a way to cause unintended pregnancy or sexually transmitted disease infection. Sabotage may be by someone acting maliciously at random (such as poking holes at the store pre-purchase) or by one of the participants as a way for either the woman or the man to attempt to cause a pregnancy when the other partner does not want it, often occurring as part of reproductive abuse.<ref name=ACOG>Committee on Health Care for Underserved Women. American College of Obstetricians and Gynecologists. February 2013
[https://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Health-Care-for-Underserved-Women/Reproductive-and-Sexual-Coercion Committee Opinion No. 554: Reproductive and Sexual Coercion] Obstet Gynecol 2013;121:411–5. PMID 23344307</ref>

The title text explains that the word was first introduced to [[Randall]] (and probably to the world) by a friend of his named Beth.

==Transcript==
:Cueball: How did you spend your morning?
:Black Hat: Feeding rocks to children in the park.
:Cueball: Your sociopathic abuse of random strangers staggers me.
:Black Hat: I aspire to have more creativity than the common asshole.
:Black Hat: I'm more of a classy asshole -- A class-hole, if you will. For example, I like poking tiny holes in styrofoam noodle cups at the grocery store--
:Black Hat: Thanks to me, someone gets surprise boiling water in the lap.
:Cueball: I am in awe.
:Black Hat: It's even more fun to do to condoms.

==References==

<references />

{{Comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Language]]

72: Classhole

2014-11-22T18:36:41Z

199.27.133.137: /* Explanation */ contraceptive sabotage is the term for acts such as poking holes in condoms - as part of reproductive abuse, reference - ACOG

{{comic
| number = 72
| date = March 6, 2006
| title = Classhole
| image = classhole.jpg
| titletext = A term coined by my friend Beth
}}

==Explanation==
This subject of this comic is [[Black Hat]] himself. He admits to being an asshole, a profanity that describes someone who does things that antagonize, irritate or anger others (either intentionally or incidentally). While a common example might be someone who weaves in and out of traffic, or someone who parks across two parking spaces, Black Hat is "more creative." This also suggests that, while most people described as assholes are either ignorant or selfish, Black Hat seems to intentionally behave this way strictly to be an asshole, and not for any self-benefit. He claims to be a "classy asshole," or as he coins the {{w|portmanteau}}, a "class-hole." He seems to equate creativity with class, although that seems like a leap. In any event, this is another early Black Hat strip which, for the first time, explicitly sets out that he goes out of his way to wreak havoc.

Among his "pranks," he suggests poking holes in grocery noodle cups. These are pre-packaged cups filled with dried noodles and dried soup mix (either in a separate pouch, or loose in the cup) to which one adds boiling water, which both boils the pasta and dissolves the soup mix to become the soup/broth. By poking holes in the cup, Black Hat ensures that someone pouring boiling water in the cup would have it leak all over them, causing them great surprise and pain.

He also suggests poking holes in condoms, which could cause even more serious consequences. This form of [http://en.wikipedia.org/wiki/Reproductive_coercion#Birth_control_sabotage| contraceptive sabotage] is a way to cause unintended pregnancy or sexually transmitted disease infection. Sabotage may be by someone acting maliciously at random (such as poking holes at the store pre-purchase) or by one of the participants as a way for either the woman or the man to attempt to cause a pregnancy when the other partner does not want it, often occurring as part of reproductive abuse.<ref name=ACOG>Committee on Health Care for Underserved Women. American College of Obstetricians and Gynecologists. February 2013
[https://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Health-Care-for-Underserved-Women/Reproductive-and-Sexual-Coercion Committee Opinion No. 554: Reproductive and Sexual Coercion] Obstet Gynecol 2013;121:411–5. PMID 23344307</ref>

The title text explains that the word was first introduced to [[Randall]] (and probably to the world) by a friend of his named Beth.

==Transcript==
:Cueball: How did you spend your morning?
:Black Hat: Feeding rocks to children in the park.
:Cueball: Your sociopathic abuse of random strangers staggers me.
:Black Hat: I aspire to have more creativity than the common asshole.
:Black Hat: I'm more of a classy asshole -- A class-hole, if you will. For example, I like poking tiny holes in styrofoam noodle cups at the grocery store--
:Black Hat: Thanks to me, someone gets surprise boiling water in the lap.
:Cueball: I am in awe.
:Black Hat: It's even more fun to do to condoms.

{{Comic discussion}}
[[Category:Comics featuring Cueball]]
[[Category:Comics featuring Black Hat]]
[[Category:Language]]

327: Exploits of a Mom

2014-09-16T00:26:33Z

199.27.133.137: /* Explanation */

{{comic
| number = 327
| date = October 10, 2007
| title = Exploits of a Mom
| image = exploits_of_a_mom.png
| titletext = Her daughter is named Help I'm trapped in a driver's license factory.
}}

==Explanation==
The title of this comic is a pun - an exploit can simply mean an accomplishment or heroic deed, but in computer science it means a program or technique that takes advantage of a vulnerability in other software. In fact her exploit is to exploit an exploit (her achievement is to make use of a vulnerability). We can also assume that she regards the name she has given her son as an extraordinary deed.

[[Mrs. Roberts]] receives a call from her son's school. The caller asked if the she really named her son <code>Robert'); DROP TABLE students;--</code> and the mom claimed that they used the nickname "Little Bobby Tables". As the full name is read into the database without "{{w|Data sanitization#SQL injection|sanitization}}" it causes the student table to be deleted.

In {{w|SQL}}, commands are separated by semicolons '''<code>;</code>''' and data is often quoted using single quotes '''<code>'</code>'''. Commands may also be enclosed in parentheses '''<code>(</code>''' and '''<code>)</code>'''. Data is stored in tables of similar items (e.g. '''<code>students</code>''') and individual entries are "rows" in the table. To delete an entire table (and every row of data in that table), you use the command '''<code>DROP</code>''' (e.g. '''<code>DROP TABLE students</code>''').

The '''<code>);</code>''' closes the current command allowing the '''<code>DROP TABLE students;</code>''' command to run. The '''<code>--</code>''' that follows it tells the interpreter to ignore everything after it so that the injection is complete. At the end, the school informs the mom that her exploit was successful and the mom reminds the school to make sure they have added data filtering code to prevent code injection exploits in the future.

The exploited vulnerability is that the single quote in the name input was not properly "escaped" by the software. Thus, when the name is embedded into some SQL statement, the quote is erroneously parsed as a closing quote inside that statement, rather than being parsed as part of the name. Lack of such escaping is a common SQL vulnerability; this type of exploit is referred to as {{w|SQL injection}}.

For example, if the site was running PHP, the code might take the student's name in a variable called $student and generate an SQL statement to check that the name is valid, like this:

<code>$sql = "SELECT * FROM Students WHERE (student_name='" . $student . "')";</code>

For a student named "Annie", this would give the following SQL command:

<code>SELECT * FROM Students WHERE (student_name='Annie')</code>

However, with Mom's exploit, this becomes:

<code>SELECT * FROM Students WHERE (student_name='Robert'); DROP TABLE Students;--')</code>

That can be seen as three statements, separated by semicolons: the <code>SELECT</code> which runs as normal; the <code>DROP TABLE</code> command which does the damage; and a comment, which consists of everything from the <code>--</code> to the end of the line (thus "eating" the <code>"')"</code> characters) and prevents SQL from saying "hold on, there's some goofy syntax in this line".

For this to work, it helps to know a little about the structure of the database. But it's quite a good guess that a student management database might have a table called <code>"Students"</code>. Mom's code also assumes that the person who wrote the SQL used exactly one set of parentheses around <code>"student_name='Robert'"</code>; that might need a little trial and error to get it to work. (Of course, most exploits of this kind are done not by social-engineering the hapless user into typing your kid's funny name, but by getting access to the system yourself and trying lots of combinations until something works, probably starting with an injection of the <code>SHOW TABLES</code> command to see how the database is structured.)

There is a site about preventing SQL injection named http://bobby-tables.com.

==Transcript==
:[Mrs. Roberts receives a call from her son's school.]
:Caller: Hi, This is your son's school. We're having some computer trouble.

:Mrs. Roberts: Oh, dear - did he break something?
:Caller: In a way -

:Caller: Did you really name your son <code>Robert'); DROP TABLE students;--</code>?
:Mrs. Roberts: Oh, yes. Little Bobby Tables, we call him.

:Caller: Well, we've lost this year's student records. I hope you're happy.
:Mrs. Roberts: And I hope you've learned to sanitize your database inputs.

{{comic discussion}}
[[Category:Comics featuring Mrs. Roberts]]
[[Category:Comics featuring Little Bobby Tables]]
[[Category:Comics featuring Elaine Roberts]]