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Comment by qume | Hacker News Reader

If pure silicon is 100% silicon atoms by definition, what is ultra pure silicon? 101%? Cool!

>That quartz is then blasted in a powerful electric furnace, creating a chemical reaction that separates out much of the oxygen. That leaves you with what is called silicon metal, which is about 99 percent pure silicon. But that’s not nearly good enough for high‑tech uses. Silicon for solar panels has to be 99.999999 percent pure—six 9s after the decimal. Computer chips are even more demanding. Their silicon needs to be 99.99999999999 percent pure—eleven 9s.

From the article. Pure/purity.

recently learned that silicon solar panels used to source their material from 'bad' computer chips silicon :)

>> Silicon for solar panels has to be 99.999999 percent pure—six 9s after the decimal. Computer chips are even more demanding. Their silicon needs to be 99.99999999999 percent pure—eleven 9s.

Yuck. Their style of reporting numbers isn't even self-consistent; an impurity rate of 1e-8 is "six 9s after the decimal", but 1e-13 is "eleven 9s".

Obviously, they're wrong about where the decimal point in a percentage is in the first place, but if they're going to invent a distinction between "9s after the decimal place" and "9s", you'd think they could try to get that right.

The “eleven 9s” is written with the earlier sentence still in context. “After the decimal” can be elided in situations like that because the literate reader knows what they’re referring to.

What does "5 nines of reliability" mean to you? "Nines after the decimal" was nonsense to begin with. But no, it doesn't make sense to assume, when someone uses established terminology, that what they really meant was to refer back elliptically to their own different idiosyncratic terminology.

Without other context, 5 nines of reliability = 99.999%. But their comment about the six 9s after the decimal is meant for readers, not a technical audience and is clear in its meaning (it's not wrong, it's emphasis). The reference to eleven 9s is perfectly consistent as a callback to the earlier comment. "Hey, remember how that one thing had six 9s after the decimal, this has eleven!" This is how writers write for long form narratives.

They didn't call it six 9s of reliability or eleven 9s of reliability. They stated a fact, again as emphasis for the readers. This is not a technical document, it's Wired.

> they really meant was to refer back elliptically to their own different idiosyncratic terminology.

It was two sentences back, not like they went the whole article and used the second expression.

Hey respected downvoters - pure means homogeneous. Can you please explain to be what ultra homogeneous means?

When discussing scientific concepts being haphazard with language seems like it should be called out, especially when the source is a respected publication like wired.

Simply take a few seconds to let us all know the error in my ways please.

In this context "pure" is meaningless (truly 100% pure silicon is impossible to obtain in quantity), whereas "ultra pure" is a technical term that refers to a specific level of purity. The meanings are context dependent.

It isn't haphazard, it's actually hyper specific and the terms have clear definitions in context. And in this case they are defined in the article.

Pure is not 100%. The article talks about 99.XXX percentages depending on application.

Please don't do flamewars on HN and for heaven's sake not nitpicky pedantic ones.

https://news.ycombinator.com/newsguidelines.html

Your argument is valid but uninteresting, hence my downvote. You should mail WIRED for such corrections instead of posting comments to HN. WIRED won't read your HN comments.

I would argue it isn’t even valid. Words have meaning in context, not isolation. There were lots of examples of words misused from their most exact dictionary definition given in this thread, which I’ll leave as an exercise to scroll up if you want to read. This was instead a pointless pedantic rant by a few folks.

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