Join students Sophie, Tomás, Emma, and Marcus during Fifth Period! This STEM comic strip chronicles the exciting and often hilarious adventures of a close-knit group of four friends as they learn about science, technology, engineering, and math from their kooky, inspiring, off-the-wall science teacher, Mr. Kepler. When they're not in class, these kids love to explore the vast world of STEM on their own, launching weather balloons, programming computer games, and cataloging insects, sometimes with unpredictable and highly entertaining results!
Check back on the first and third Friday of every month for a new Fifth Period strip!
Prime Time for Marcus
Don’t worry guys—the homework will stop one day, but the prime numbers won’t. Prime numbers are so much more than weird, indivisible numbers that go on forever though—some of their properties make them extremely useful for cryptography. You probably already knew that a prime number is only divisible by 1 and itself. (For example, 13 is a prime because can only be divided by 13 and 1) and that these numbers get further apart as they get larger (…5, 7, 13, 17, 23, etc.). Mathematicians believe that all numbers in the universe are composed of prime numbers. As numbers get larger, it gets harder and harder to break them down into their prime number parts. By the same token, it gets harder to determine whether a number is a prime as it gets larger. This property of prime numbers is part of number theory and makes things like Internet encryption possible—the kind of thing that allows your parents to pay their bills online and not worry too much about computer hackers!
Think of encryption this way: Say you have a computer file protected with multiple passwords—in this case, the passwords are prime numbers. You can open the document because you know the passwords, but a hacker must try all sorts of combinations to get access to all that private information, and he’ll likely write fancy software algorithms to get his computer to try all those combinations. If the prime number passwords are smartly chosen, the hacker has almost no chance of getting access to your data, regardless of how incredibly smart or determined he is.
Try it yourself!
There’s a simple, visual way to determine whether you have a prime number of any group of objects. Take for instance a bag of candy—can you arrange the pieces into a rectangle of any size, with columns that have the same number of pieces? If so, you have a non-prime or “composite” number, but if you have a few pieces left over, you have a prime number. BUT, are you really, really sure? Can you rearrange the pieces with a different number of columns and rows to get that perfect rectangle shape?
Now, imagine having to do this with hundreds and hundreds of candy pieces—a nearly impossible task, or at least very hard, even using a computer! For large numbers, there are lots and lots of combinations that must be tried!
Just a glimpse of how prime numbers’ mysterious nature makes them perfect for encryption purposes.