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Cake day: June 16th, 2023

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  • Scroll down a bit in this article. There’s a list of what each of the available keys are required to provide. A “key” in this context is basically a notch in a certain location, which then defines the meaning of the various pins of the connector. Some devices have multiple keys, as some of the specifications have a common subset. Like key A+E is common, because E provides almost everything that A does, so a device that only requires the common interfaces can work in both. Cars that rely on one of the exclusive interfaces will have the specific key of course. This A+E communication is often used for WiFi cards.

    Sockets always only have one key though, for obvious reasons.

    Edit: correction/clarification




  • Normal bikes that you just push aren’t that stable without a rider, but you can get it some distance. They still fall over rather quickly. That’s mostly the form of the handlebars like gnu commented. And yes, without a rider, the gyroscopic effect is relevant. A bike weighs let’s say 15 kg, and a rider is commonly like 75kg. Of course removing like 80% of the weight changes if the gyroscopic has a meaningful influence. Add the rider back, and it becomes negligible again.

    This is of course even more pronounced if you push only a wheel with nothing else, then there’s nothing left but momentum and the gyroscopic effect.

    The reason you lean into a turn is exclusively the centrifugal force (not sure that’s the right twin), if you don’t you fall over because you have nothing to turn against. Changing direction needs something to push against.


  • The gyroscopic effect of slowly spinning, light bicycle wheels is negligible compared to the weight of the bike and it’s rider. If it was what keeps you upright, riding a tiny scooter-thing with skateboard/inliner wheels would be impossible. I mean those without motor, pedals, where you push yourself forward with one foot on the ground), often for kids.

    What actually keeps you upright isn’t a physical effect, but just training your brain to instinctually keep you upright. While you’re moving, turning the handlebar effectively moves the bike below you left and right. So if you start tilting to the right, you turn right (slightly) so the bike/scooter is moving below you to compensate. That’s why learning to ride anything that is balancing on 2 wheels takes a relatively long time, but only once. Then your brain knows what to do, and it just works without thinking about it.










  • That’s not actually a solution when talking single-use either. Remaking the bottles from recycled glass is incredibly energy intensive and not an environmentally friendly process either. Multi-use bottles are much better, but the cleaning required also isn’t that simple and also relatively energy intensive (far from remaking the bottles of course).

    There’s also practical downsides to glass (heavy, breakable), but those are subjective and their relevance highly depends on the use case.

    Ideally, we wouldn’t buy stuff to drink in any kind of bottle, but just use tap water. possibly just buy some concentrated stuff to then make your actual drink at home. Nothing beats the effectiveness of transporting water through a simple pipe, but that isn’t even possible everywhere in the world due to drinking water quality issues…



  • The “key” of an m.2 defines what the pins mean, basically what signal they carry (PCIe, USB, …). There’s a nice table here, if you scroll down a bit. Some are extensions to others, and are pin compatible (meaning the things they have in common are on the same pins).

    A key and E key are very similar, while E just provides a few more interfaces, but importantly A doesn’t provide anything the E doesn’t. So any card that can work in A can also work in E. This is why A+E is so common: they don’t require the Mainboard to provide E, only A, but both will work so both notches are present.