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| Ground Effect |
 Title text: Runners looking for aerodynamic advantage typically wear sneakers because some fancy dress shoes can create wingtip vortices. |
Explanation
The "ground effect" is an aerodynamic phenomenon, which reduces lift-induced drag when an airfoil is close enough to the ground (typically described as being within one wingspan) that wingtip vortices are significantly affected. Some vehicles and many birds and bats make use of this effect to increase their efficiency of operation.
This comic uses a different interpretation of the term 'ground effect'. Runners depend on their feet making contact with the ground in order to push against it and generate forward motion. In order to do this, all of them must be within one (their own) body length of the ground in order to push against it. This could be considered to be reducing their 'efficiency' to zero. This process has little to do with aerodynamic effects.
The title text is a pun. In airplane aerodynamics, wingtip vortices are longitudinal vortices (horizontal whirlpools parallel to the airplane fuselage) that a wing creates near the tip when it generates lift. These create unhelpful drag without adding lift, so modern airplanes generally have winglets at the end of the wings to make these vortices smaller. In fashion, there is a style of dress shoe called wingtips with small holes in the upper leather in a pattern that somewhat resembles a bird's wings. In reality, runners would not wear dress shoes because they would be heavy, uncomfortable, and restrictive, and they typically have soles that do not provide sufficient grip on the running surface.
Transcript
- [Five Cueballs are shown in the panel. At the left, two of them are floating in the air, flailing their arms and legs as they float at least 12 feet off the ground. At the right, three others are running to the right in a normal way. A dotted line is shown above the tops of these three runners' heads, and a regular line below them indicates the ground. An arrow points down toward the dotted line and another arrow points up toward the regular line behind the runners.]
- [Caption below the panel:]
- The "ground effect" explains why sprinters can run most efficiently if they stay within roughly one body length of the surface.
Trivia
This comic seems only to have been published on a Thursday, i.e. 1st October, but the official archive log gives it the date of the Wednesday slot within the release cycle that is expected. It is unclear whether Randall forgot to release this on the regular Monday, Wednesday, Friday schedule or if there were other reasons for the delay. The exact timings of comics is quite variable, and may in some cases be confounded by timezone issues, but it is not unknown for an official Monday comic to be released at a time that can only be considered Tuesday, etc, and this is not usually acknowledged by Randall unless it is an event-driven comic that needs additional work, which may or may not prompt some other comic(s) to be published in the interim.
This Week's Explanation for Improvement
As part of the Explanation Improvement Project, each week the community selects one older, stagnant, or otherwise neglected explanation to expand and polish together. This week's pick is comic 172: Skateboarding is Not a Crime, you can help us by editing its explanation!
To get involved with the project, you can also nominate an explanation that you think should be improved, or vote on current nominations!
| Skateboarding is Not a Crime |
 Title text: 'Arrest me, I'm a skateboarder' is an even more obnoxious variant. |
Explanation
|
Welcome to This Week's Explanation for Improvement! Anyone is encouraged to help explain comic 172: Skateboarding is Not a Crime; click here to get started! If you are new to wiki editing, you can read our editing FAQ for guidance. Here are some suggestions for improving this explanation: .svg){kind=icon} we have finished. great job everyone! |
Skateboarding culture emerged in the 1980s, especially among young people (high schoolers, college students) as a countercultural movement initially associated with the "punk" movement. In addition, because skateboarding can take place in public locations with railings and benches, many cities have adopted specific measures to either increase the difficulty of skateboarding (Skatestopper), or by trying to pass laws to prohibit the act of skateboarding in public parks. In addition to the stated public safety concerns of fast-moving skateboarders among pedestrians, many cities unfairly associate skateboarders with those who drink, do drugs, or engage in acts of juvenile delinquency, such as truancy or underage drinking.
As a result, the skateboarding subculture has taken up the slogan "skateboarding is not a crime" as a protest against these restrictions from cities. This slogan began in 1987, and since then, several skateboard manufacturing companies have adopted it. At one point, the slogan was a countercultural push against those who would consider skateboarding to be a crime, but as the phrase became more popular (by 2006, the time at which the comic was posted), there was likely a backlash against the slogan. Perhaps some people, both within the community of skateboarders and outside, would consider this sticker to be obnoxious, or to appear to have a persecution complex. For instance, in this comic, the slogan is the *only* sticker displayed on these lockers, perhaps put there as a way of the locker owner trying to stand out, in a "not like the other girls" manner.
Randall apparently really does not like these stickers and states that when/if he becomes president (a common expression that is equivalent to "If I were in charge, ..."), any and all displays of stickers bearing the phrase (like the one on the locker in the comic) will be considered a felony, though skateboarding itself will still be legal. Actually implementing this would be against the first amendment and would be unlikely to ever become a real law. Even if it did, it is so trivial and disproportionate that it is unlikely to be enforced. Still, some schools and other establishments ban or restrict stickers on lockers, and may use a similar rule.
The title text comments on another protest phrase, "arrest me, I'm a skateboarder", that Randall appears to hate even more than "skateboarding is not a crime", potentially for the more standoffish tone of the message. It is unsurprising that he hates this phrase, as it has a similar message and tone.
Transcript
- [A set of lockers, that are dark pink, blue, yellow, dark pink then blue. The yellow locker at center has a white sticker attached to it at an angle reading "Skateboarding is not a crime".]
- [Outside of the Panel] When I'm president, skateboarding will still be legal, but display of those stupid stickers will be a felony.
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