I'm hungry! And I've got my bag of mice... Yummy! But what's this? a hole in the bag?? They're escaping!!! Aha, tiny mice, you might tumble past our paws, but you can't hide!! We'll catch you in our mousetrap down below!!
Hmm... now why is it that most of the mice are falling into the middle of the mousetrap, out of our reach???		Let's wait and watch them for awhile and see what happens. (Oh!  Tap the mousetrap with your paw and they'll freeze!   Now tap again...) While we wait here licking our chops, read on down below...

What's going on here??? Our mousetrap is called by several names:  a bell-shaped curve... a normal distribution curve...  a Gaussian curve (named for a German mathematician of the 19th century). A bell-shaped curve shows how likely it is that an event will turn out a certain way (the average way).   Our mousetrap predicts that more mice will tumble toward the middle than the edges.   Can you think why? Do the mice always pile up to fit the mousetrap exactly? Why or why not? What do you think would happen if you ran this experiment over and over again?   (Hit the refresh button on your browser a few times to see.) A bell-shaped curve that is tall and narrow means we can predict the results with greater confidence.   A bell-shaped curve that is wider means that the results might vary more. Whenever there is variation in the world around us, we can create a distribution curve to describe it.  If you graph the weights of all the cats in your neighborhood, you would see a bell-shaped curve.  If you graph how many times you and your classmates can jump in one minute, you would see a bell-shaped curve.   Why don't you try it? As for our little mice... our mousetrap curve is rather wide because these mice are a bit bouncy! (but tasty)

This applet has been adapted by Maurici Carbó Jordi of nummòlt
from Ball Drop by David Krider at the Java Boutique.
tiny mouse graphic by Emily Petti, age 9.
text and other graphics © 2003 - by Wendy Petti of Math Cats. All rights reserved.