Computer technology is a field that deals with very large numbers. A byte is the unit used to measure information related to computers. My computer has 65,536 megabytes of "built-in memory". A "kilobyte" (K) is one thousand bytes, and a "megabyte" (MB) is 1 million bytes. How big is a kilobyte? A short page of text (perhaps 2 paragraphs) might be about 15 K. A paperback novel might contain 1 MB of information.The complete works of Skakespeare is about 5 megabytes.
A Gigabyte is 1,000,000,000 bytes (that's 1 billion bytes). 20 Gigabytes would contain a good collection of the works of Beethoven.
For more information about the world of computers, check out this interesting website:
Biology
Feeling sorry for the U.S. Census as it single-mindedly plans to count more than a quarter-billion Americans? Then spare a tear for the poor microbiologist, eager to pin down the total number of bacteria and other prokaryotes on Earth. (The prokaryotes comprise two of the broad kingdoms of life -- bacteria and archaea. The third kingdom -- eukarya -- contains all organisms with cellular nuclei, including fungi, plants and animals.)
.
There are lots of prokaryotes. Even though each one weighs less than a trillionth of a gram when toweled dry, overall they weigh about as much as all the plants in the world -- roughly a gigaton.
So how many prokaryotes share the planet with us? According to William Whitman, a microbiologist at University of Georgia, the number is 5 x 10 to the 30th. This is a big number by any standard. If you had that many pennies, Whitman and colleagues David Coleman and William Wiebe calculated, they would make a stack a trillion light years long.
Just where are all these prokaryotes? As we indicated, some bacteria live in the human gut -- a total of 3.9 x 1023 among all six billion of us. (Before you down another tetracycline as your part in the global crusade against bacteria, remember that most intestinal bacteria are helpful.) Furthermore, the vast majority of prokaryotes live under land or the sea floor, not in us. In fact, 92 to 94 percent of all prokaryotes live underground lives of quiet desperation, hidden in the cracks and pores of rock and sediment, lacking sunlight, fresh air, even cable TV.
A whale of a census! Unable to count bacteria individually, Whitman and colleagues opted for a sampling technique. They divvied the world into representative habitats, like forests, deserts, freshwaters, and shallow and deep ocean waters. Then they scoured the science literature looking for studies on the density of bacteria in each habitat. From there it was simple multiplication -- size of habitat in milliliters times number of prokaryotes per milliliter equals total number of bacteria in that habitat.
The math showed that the top eight meters of soil carry 26 x 1028 prokaryotes, and all aquatic habitats carried 12 x 1028. But the real jackpot lies underground. More than 8 meters below the land surface, they found between 25 and 250 x 1028 prokaryotes. And beneath the ocean floor live a staggering 355 x 1028 organisms without nuclei.
This green alga is colonized by colorless, rod-shaped iron bacterium Leptothrix discophora. These bacteria also colonize soda bottles, tennis shoes, styrofoam cups, plastic bags -- even microscope slides.
Photos by Eleanora I. Robbins, courtesy of USGS Bio-blitz. The Why Files -- David Tenenbaum http://whyfiles.news.wisc.edu/shorties/count_bact.html
The Automobile
Industry
Reading a magazine just the other day, I came across an advertisement from Ford Motor Company. It seems that they have come up with a foolproof method for keeping your car from being stolen! They call it Securilock ©. "Each car key has a unique code that matches the one in your vehicle. And there are 72 quadrillion possible codes. We could put a different one in every vehicle we sell worldwide for the next four billion years.
Now how did they figure out that number? For this, you need to know a little bit about probability. If you flip a coin, there are only 2 possibilities: heads or tails. So a statistician would say that you have a "1 in 2 chance of getting heads, and a 1 in 2 chance" of getting tails." Probability is defined as a fraction, like 1/2 or .5. Written as a common fraction, like 1/2, this means 1 is the number of "successes" (you got heads) divided by 2, the number of possibilities.
If the probability of getting heads is 1/2 when you toss the coin once, what is the probability of getting heads both times when you toss the coin twice? Simple, you just multiply\y the individual probabilities: 1/2 times 1/2, or (.5)(.5) = .25 or 1/4.
So, given the 10 digits 1,2,3,4,5,6,7,8,9,0 if Ford makes a one-digit code for your key, then a thief has a 1 in 10 chance of guessing the right one. That 's 1/10 or .1, mathematically speaking. If Ford uses a 2-digit code, then the probability of the thief guessing BOTH digits is 1/10 times 1/10, or 1/100. in decimals, (.1)(.1) = .01
The probability of guessing a 7-digit code is (.1)(.1)(.1)(.1)(.1)(.1)(.1) which is .0000001 Rather unlikely!
Ford then goes on to say "You're 10,000 times more likely to win the lottery than to steal my car."
Test Question #9: What are the chances of throwing a coin 10 times and getting heads every time?