5 ms·

45 nanograms per liter means about 1 cup of coffee every 6000 liters of water. This doesn't sound like a lot, but 6000 liters fit in a cube of ~1.8m - and there

by miahi 14y ago

45 nanograms per liter means about 1 cup of coffee every 6000 liters of water. This doesn't sound like a lot, but 6000 liters fit in a cube of ~1.8m - and there is a lot of water out there. The biological half-life of caffeine (how long it takes the human body to eliminate it) is not important here; it's not about humans but the sea life; nobody knows what happens to marine life in a continuous exposure to traces of caffeine and other substances.

switch007 14y ago
Slight miscalculation: 6,000 litres fits in 6m3 not 1.8m3 (ref: http://www.wolframalpha.com/input/?i=6000+litres+in+meters+cubed http://www.wolframalpha.com/input/?i=6000+litres+in+meters+c...)
- corin_ 14y ago
  He said a cube of 1.8m, not 1.8m3 - he means 1.8m x 1.8m x 1.8m, making it easier to visualise :)
- computator 14y ago
  No, the grandparent was right. He's talking about how big a cube could contain 6000L, but you're calculating the volume of 6000L. Simple way to visualize this: Think about the difference between a 4-foot square and 4 square feet. The former is a much bigger area.
  - switch007 14y ago
    Of course! Thanks :)
gshubert17 14y ago
If 1 cup of coffee contains 150 milligrams of caffeine (http://www.wolframalpha.com/input/?i=how+much+caffeine+in+1+cup+of+coffee http://www.wolframalpha.com/input/?i=how+much+caffeine+in+1+...) that would take 3.3 million liters (not 6000).
pfraze 14y ago
Judging from personal experience, they'll probably get a lot more work done, but make more frequent trips to the restroom.
refurb 14y ago
Wait, what? If we assume 100 mg in a cup of coffee, we can do the math by: 1.010E^(-1)/4.510E^(-8) which is equal to 2.22*10E^(6) or 2.22M liters of water. You're only off by a factor of 370! Since one cubic meter is 1000 liters, you're looking at a cubic body of water that is 13 meters or ~40ft on each side.
- drothlis 14y ago
  What does "x * 10E^(y)" mean?
  - g_lined 14y ago
    http://en.wikipedia.org/wiki/Scientific_notation http://en.wikipedia.org/wiki/Scientific_notation
    - sesqu 14y ago
      You'll notice that the link you provided does not actually include an example of the usage you intended it to serve as a reference for. This is probably because the usage is nonstandard, which is probably why GP asked their question. It's reasonable to assume that "x * 10E^(y)" was meant as a notation for "x * 10^(y)" = "xEy", but many mathematical notations are overloaded. I have no way of knowing whether GP was genuinely confused, or merely trying to point out the nonstandard usage, but I prefer to believe the former.

by miahi 14y ago

switch007 14y ago

Slight miscalculation: 6,000 litres fits in 6m3 not 1.8m3 (ref: http://www.wolframalpha.com/input/?i=6000+litres+in+meters+cubed http://www.wolframalpha.com/input/?i=6000+litres+in+meters+c...)

corin_ 14y ago
He said a cube of 1.8m, not 1.8m3 - he means 1.8m x 1.8m x 1.8m, making it easier to visualise :)
computator 14y ago
No, the grandparent was right. He's talking about how big a cube could contain 6000L, but you're calculating the volume of 6000L. Simple way to visualize this: Think about the difference between a 4-foot square and 4 square feet. The former is a much bigger area.
- switch007 14y ago
  Of course! Thanks :)

gshubert17 14y ago

If 1 cup of coffee contains 150 milligrams of caffeine (http://www.wolframalpha.com/input/?i=how+much+caffeine+in+1+cup+of+coffee http://www.wolframalpha.com/input/?i=how+much+caffeine+in+1+...) that would take 3.3 million liters (not 6000).

pfraze 14y ago

Judging from personal experience, they'll probably get a lot more work done, but make more frequent trips to the restroom.

refurb 14y ago

Wait, what? If we assume 100 mg in a cup of coffee, we can do the math by: 1.010E^(-1)/4.510E^(-8) which is equal to 2.22*10E^(6) or 2.22M liters of water. You're only off by a factor of 370! Since one cubic meter is 1000 liters, you're looking at a cubic body of water that is 13 meters or ~40ft on each side.

drothlis 14y ago
What does "x * 10E^(y)" mean?
- g_lined 14y ago
  http://en.wikipedia.org/wiki/Scientific_notation http://en.wikipedia.org/wiki/Scientific_notation
  - sesqu 14y ago
    You'll notice that the link you provided does not actually include an example of the usage you intended it to serve as a reference for. This is probably because the usage is nonstandard, which is probably why GP asked their question. It's reasonable to assume that "x * 10E^(y)" was meant as a notation for "x * 10^(y)" = "xEy", but many mathematical notations are overloaded. I have no way of knowing whether GP was genuinely confused, or merely trying to point out the nonstandard usage, but I prefer to believe the former.