Very roughly how many water molecules would you guess there are in a single cell? Within a couple of orders of magnitude? I got it quite wrong.
-
Show this thread
-
I guessed off-hand “a billion” which I think was just my brain’s way of saying “wow, a really big number!” But it’s WAY too small.
3 replies 0 retweets 7 likesShow this thread -
There’s a bunch of different numbers you can find on the web. Some of them are definitely way off. But there’s a wide range of values that seem reasonable (to me) because cells vary in size over several orders of magnitude.
2 replies 0 retweets 3 likesShow this thread -
A water molecule is roughly 3Å (I remembered this!). An Å is 10^-10m (I remembered this too!) How big is a cell? (I didn’t remember this, if I ever knew!) 10μ is too small and 100μ is too big (although for a Fermi estimate, but might be reasonable).
3 replies 0 retweets 2 likesShow this thread -
So call it 30μ, i.e. 3*10^-5. Then the ratio of linear dimensions is 10^5, or volumetrically 10^15. But water isn’t the whole of the cell, so less than that. Maybe 10^14. This is larger than most numbers I found on the web, but not way off.
1 reply 0 retweets 2 likesShow this thread -
Several tweeps did estimates based on total mass of human body divided by the number of cells, and came up with similar numbers. I wouldn’t have thought of that approach!
1 reply 0 retweets 2 likesShow this thread -
I think my original guess was dumb in an interesting way. 10^9 is the cube of only 10^3. Would it be reasonable for a cell to be 10^3 water molecules across? If you think about all the stuff that’s crammed into a cell, made of proteins, and proteins are WAY bigger—no, not 10^3.
1 reply 0 retweets 3 likesShow this thread -
The lesson for me is that cubing numbers makes them grow faster than I realized at a gut level. “Polynomial algorithms are fast!” is not so true for O(n^3).
5 replies 0 retweets 6 likesShow this thread -
This Tweet is unavailable.
-
This Tweet is unavailable.
Oh, good. It’s an influential classic, but I think maybe underrated currently.
Loading seems to be taking a while.
Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.