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>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 ca

>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.

agumonkey 8y ago
recently learned that silicon solar panels used to source their material from 'bad' computer chips silicon :)
thaumasiotes 8y ago
>> 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.
- Jtsummers 8y ago
  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.
  - thaumasiotes 8y ago
    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.
    - Jtsummers 8y ago
      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.

agumonkey 8y ago

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

thaumasiotes 8y ago

>> 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.

Jtsummers 8y ago
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.
- thaumasiotes 8y ago
  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.
  - Jtsummers 8y ago
    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.