tag:blogger.com,1999:blog-2818228120441466850.post3645394651302190524..comments2010-04-30T14:34:01.808-07:00Comments on Mayonnaise Bathtub: MEGA PIRANHA (2010) - part one of twoChaia Milsteinhttp://www.blogger.com/profile/02323371613659813840noreply@blogger.comBlogger5125tag:blogger.com,1999:blog-2818228120441466850.post-4974654400837420522010-04-30T14:34:01.808-07:002010-04-30T14:34:01.808-07:00I applaud your calculations. Thank you, sir.
Ther...I applaud your calculations. Thank you, sir.<br /><br />There still remains the question of how the last fish standing might affect the balance of the universe - perhaps a study for another time.Chaia Milsteinhttps://www.blogger.com/profile/02323371613659813840noreply@blogger.comtag:blogger.com,1999:blog-2818228120441466850.post-55376620821411719782010-04-24T07:23:47.228-07:002010-04-24T07:23:47.228-07:00Oh, and I forgot to answer the last question -- ho...Oh, and I forgot to answer the last question -- how big would the last fish standing be? But I feel unqualified to answer that question; it leaves the realm of applied mathematics and involves animal behavior, efficiency of digestion, and some other factors. We'd need to consult a biologist -- maybe Tiffany? But I suspect that'd be one whoppin' big fish.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2818228120441466850.post-81211845492524560732010-04-24T07:19:55.044-07:002010-04-24T07:19:55.044-07:00Well, while area increases as a square of length (...Well, while area increases as a square of length (assuming proportional growth), weight increases as a cube of length, because weight can be approximated as a measure of volume. So since length is growing by a factor of 2 every 36 hours, weight is increasing by a factor of eight. Hence:<br /><br />6.5 lbs * 8^14.09 or 3.447 * 10^13 lbs <br /><br />per fish. Since we started with 200 fish, that's a total of 6.894 * 10^15 lbs of fish altogether.<br /><br />Of course, I've done a lot of hand-waving here -- I assumed 200 fish to start with, fish aren't perfectly rectangular, etc. But I feel like this is a good first approximation.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-2818228120441466850.post-19507749258264705432010-04-24T01:47:19.672-07:002010-04-24T01:47:19.672-07:00Keep it coming, please! Assume each piranha has a ...Keep it coming, please! Assume each piranha has a starting mass of 6.5 lbs. Uh, then what? I'm only good at fake applied math.Chaia Milsteinhttps://www.blogger.com/profile/02323371613659813840noreply@blogger.comtag:blogger.com,1999:blog-2818228120441466850.post-21572126930628817092010-04-23T18:47:59.131-07:002010-04-23T18:47:59.131-07:00Well, the average piranha is about 8 inches long. ...Well, the average piranha is about 8 inches long. If we assume, for ease of calculation, that each piranha is somewhat less than 4 inches wide, then an 8-inch square would accommodate 2 piranhas. The only remaining piece of data needed is how many piranhas you start with. I'm going to pull a number out of thin air -- let's say 200. So 200 piranhas cover 100 8-inch squares. That means that their initial total area was 6400 sq in (100 * 8^2).<br /><br />Now I'm not sure what "double in size" means here, but, again, for ease of calculation I'm going to assume that this refers to length, and that the piranhas grow proportionally, so that in 36 hours a piranha would go from 8 inches to 16 inches in length, and two piranhas would now cover a square 16 inches on a side.<br /><br />But of course that means that your piranhas are now covering an area FOUR times larger than they were 36 hours before, because area multiplies twice as fast as length.<br /><br />The surface of the earth is approximately 7.9 * 10^17 square inches. <br /><br />Define T as time in hours that it would take to cover the planet with piranhas. Define X as T/36 -- X is, in other words, the number of 36-hour periods it would take to reach T. Then:<br /><br />(6400 sq in)*(4^X) = 7.9 * 10^17 sq in<br /><br />or<br /><br />X = log base-4 of (7.9 * 10^17)/6400<br /><br />According to a logarithm calculator I found on the internet, that's about 14.09, so<br /><br />T = X * 36<br /> = 507.24 hours, or about 21 days.Anonymousnoreply@blogger.com