Saturday, June 20, 2009

I have a question

What difference is there between "oval" and "ellipse"? Do you chose the word case by case?
in many picture books about shapes I have usually "oval" is introduced, but the other day I knew, at math lesson ellipse is used. Is it right?
http://www.mathsisfun.com/area.html

Are they same?, just the difference is depending on the world? (It means math world, or usual world)
If you are free, please teach me.

4 comments:

Tim Frost said...

In my opinion this is a matter of ordinary or casual words in one case, and exact mathematical words in the other case. Young children will be told the ordinary words at first, then when they start to learn mathematics more seriously, the other words will be used. The casual words are generally simpler to say and to spell. There are several examples:

Ordinary, casual ----- Mathematical, formal
Oval --------------------- Ellipse
Ball or globe ------------ Sphere
Oblong ------------------ Rectangle

(I hope this table looks OK)

Some shapes do not have any casual word: triangle, square, circle.

Anonymous said...

Thanks Tim, "oblong" is the first word for me, kids use this word, isn't it.
Today I'm going to listen to RAKUGO in English.

mss @ nipponDAZE said...

I had to look this up. While I agree that oval is the more everyday word and ellipse is the more mathematical word, there is a fine distinction.

According to my dictionary, an ellipse is a special kind of oval: "a regular oval shape, traced by a point moving in a plane so that the sum of its distances from two other points (the foci) is constant, or resulting when a cone is cut by an oblique plane that does not intersect the base."

An oval can be egg-shaped (with one end larger than the other) but an ellipse cannot.

So, all ellipses are ovals. But not all ovals are ellipses.

Same with rectangles and squares. All squares are rectangles. But not all rectangles are squares.

Anonymous said...

Hello, Ms.Stevens
How are you doing? Thanks for your comments.
Yes, yes, Eggs are ovals, and not ellipses.
Once I was gotten a question, "eggs are "DAEN"?
The answer is "no", Eggs are egg-shaped.
"DAEN" means ellipse.