How do you make use of it? Is it basically logarithms of values? So add them together to multiply them? I don't know if I quite understand how the units would work.<p>As an example, "how long would it take for everyone in a large high school to microwave their meals if they all did it sequentially?".<p>People in a large high school is *4* (let's say about 3000 people).<p>Microwaving a meal is *2* (let's say 5 minutes).<p>So by Napkin Math we get 4+2=*6* which is a *large metropolitan area*.<p>Oops. I mean 11.6 days.<p>And with normal multiplication, 3000 * 5 = 10.4 days, so 11.6 days is a pretty good estimate.<p>So I think the answer is indeed "add the numbers together to multiply them", and be careful that you understand what units you're using.
It is generally a good mental tool.<p>Yet, without explicitly saying it's about (base-10) logarithms, it is preaching to the choir - either you already know that, or won't learn either.<p>Pet peeve - while most numbers make sense, this not, by a quite a large number:<p>> -10 practically impossible, every atom in your body quantum tunneling simultaneously one foot to the left<p>I don't want to do maths here, but for a single particle to happen that, it would be a totally different scale (I don't know, maybe closer to -10^10^10).
The one that doesn't make sense to me is "Days per $1000," because it's the only one (that I saw) where each line has an order of magnitude <i>plus</i> an addition unit, and that unit is often different from the one in the heading.<p><pre><code> -2 hours minimum wage day's work, small coffee shop daily revenue
-1 days entry-level weekly salary, independent contractor daily rate
0 weeks average monthly rent payment, typical car payment
</code></pre>
Is the difference in order of magnitude between the first two just one (-2 to -1) or 2 (E-2 hours vs E-1 days)?<p>And how is "0.1 days per $1000" an entry-level <i>weekly</i> salary? Now we have days and weeks in the same sentence.
Reminds me of the Jeff Dean "Numbers you should know" schtick about latency.<p>Other people are asking about how to use this "tool", I think it's just a rough reference. I almost see it as a kind of art/poetry, the way it's presented.
From the source (and <a href="https://bsky.app/profile/taylor.town/post/3lkl4rbfmnc2e" rel="nofollow">https://bsky.app/profile/taylor.town/post/3lkl4rbfmnc2e</a>):<p><pre><code> <meta name="description" content="Logarithmic tables for estimations."></code></pre>
Always thought something like this would be really nifty if paired in real-time with quantities we interact with in a daily basis.<p>Oh, it was a large scam? Hundreds of people participated? Basically if an extended family reunion or apartment building full of people. Not as hard to imagine.<p>The hope would be to better calibrate our own magnitude of reactions against the numbers we see
I work with storage, and "how long does it take" questions come up a lot - filling an HDD, wearing out an SSD, etc.<p>A day is about 10^5 seconds. 10^6 seconds is about a fortnight. A year is about 10^4 hours, or 3<i>10^7 seconds, so a billion seconds is about 30 years.<p>Typically the numbers you're multiplying are vague enough that these numbers are more than accurate enough - e.g. if you want to support 20MB/s for a year, back of the envelope says 600TB, exact says 630.72. You typically picked "20" out of thin air, and unless you have a </i>very* specific use case (e.g. fixed-rate video streams) it's probably only accurate +/- 50% at best.
Some of those are way off, IMO:<p>- What CPU makes a thousand cycles per second?<p>- How is fastest electronic switching slower than fastest computer operation?<p>- AFAIK, DDR5 access time is -8 or -7, not -6.<p>- Earth rotation frequency is -5, not -1.<p>- Infrared frequency is more like 14 or 13, not 12.
An unforgettable anecdote from an electrical engineering professor I had, some 20 years ago.<p>Engineering math works like this: if it's an order of magnitude bigger, round it to infinity. If it's an order of magnitude smaller, round it to zero.<p>Prior to teaching, he'd spent a career working on missile guidance systems.
If I remember right Isaac Asimov wrote down similar notes on scale and they were publish but I can’t remember what the book was called. I used to do the same think when I was a kid. A teacher saw me doing it and mentioned the book. It haunts me to this day.
-1 for Hertz is listed as "earth rotation cycle, tide changes, circadian rhythm", but 1e-1 hz is just a cycle time of 10 seconds. More like how often waves crash on the beach.