## Tuesday, July 17, 2007

### Jar or Bottle

Last night at dinner I was opening a small spherical glass container of mustard, and my husband and I got into a discussion on whether it was a jar or a bottle. Then we started thinking of other glass containers and tried to sort them into the jar and bottle camps. Yes, I know, scintillating. Tonight maybe we'll discuss pennies: pros and cons.

Of course then I started thinking of geometry when we hit the unit of being precise with definitions of triangles and squares and such. I looked up the jar/bottle definitions via google, and I'm not completely impressed with the output. The word "wide" is used, and I think that's subjective. And the jury is still out on the mustard bar/jottle.

1. A cool math-y conversation.

What has always fascinated me, but I don't even know know how to start investigating it, is the shape formed by a fluid in the state of being poured.

If I wanted to make a sculpture of milk being poured from a jug to a cup, what shape is the milk? It is smooth, but has little folds that seem to be at regular intervals.

2. I say if the container has a neck, and by that I mean it narrows at the top with at least some section of negative curvature, then it is a bottle. If it doesn't narrow at the top, or if the curvature is positive, then it is a jar.

3. Anonymous10:03 PM

Heidi: hmmmm, and I wonder if the shape of the container top you're pouring the milk from changes the fluid shape. I'll have to start playing with my food and observing. Thanks for a future conversation topic.

Tony: so even if, say, the container is a total of 2 inches tall, with the bottom 1.5"s being of a round shape, say 3" diameter, and the top 0.5" curves in a wee bit (but is still wide), that would be a bottle in your world.

Maybe this is one of those fruit/vegetable types of discussions and there are containers that could be in both camps.