I recently got my flu and COVID boosters this fall and afterward my arm was really sore. What is causing the ache? Is it the physical harm caused by sticking a needle in my arm? Is my body's immune reaction in just that location the main source of pain?

I don't have allergies to anything and don't feel otherwise ill. Just wondered whether it was more of a physical thing or chemical/immune thing.

I often have saunas, and they're my version of shower thoughts. I can't help staring at the sand timer in there and wondering how accurate it really is.

- Is there an exact mass of sand that corresponds to a given length of time?

- Do different types of sand produce different times?

- Is there a set calculation linking the width of the aperture to the time it takes the sand to fall?

- Does the angle of the timer when flipped affect the time taken?

- Does the heat in the sauna affect it too (usually my sauna is around 80 degrees Celsius)?

Curious to know. Thanks in advance, everyone.

If a person who was born blind were given a procedure to be able to see, would they be horrified by what humans actually look like? Also, would suddenly knowing what colors look like and the world around them looks like be overwhelming? Like when we try to imagine a new color but can’t?

I feel like the obvious answer is yes, electricity being used reduced the number of house fires because there's no more open flames inside homes, but also house fires are caused largely now by electrical devices, heaters, chargers or before the led light bulb boom, bulbs. So I wonder how much the frequency really changed, and if we're better off now than back then

Another thing to consider is the fact that people were more cautious around flames than they are around electrical devices that we leave plugged in passively

Obviously, most states use first past the post, but there are some, like Alaska, that use IRV. It’s better, but not perfect, as Arrow’s Impossibility Theorem says it can’t be. I don’t really understand it though, so my question for Hannah and Michael is: could you explain AIT, and what are your favorite voting systems? (I like Duncan Black’s system, which is Condorcet with a Borda fallback)