Algebra II, the parabola lesson

 

Mr. Franklin points to a minimalist sketch.  ‘Alright people, today the focus is on, well, the focus.’  His triangular brows rise. Glacial blue eyes peer over rimless lenses, perusing our sea of faces.

 

All our math lives, we only knew about straight lines. Eyes roll, wander, glance sideways. This was a tough sell to teenyboppers.

Undaunted, Mr. Franklin introduces us to the parabola and its friends through the magic of wax paper.

We have no clue what a focus and a directrix are.  (We heard it wasn’t going to be on the test.  Just sayin’.)

 

Anyway, class that day was a hoot. And I did learn this much:  a parabola is a special arch-shaped curve.  But not just any arch-shaped curve. Each and every point on a parabola is at an equal distance from a fixed point ( the focus !!!) and a fixed line (the directrix).

 

So after applying the ruler to the wax paper and making a gazillion folds, I finally got a curve.  And that was that.

 

These days, teachers use Angry Birds and lots of cool real-life examples.

I don’t remember Mr. Franklin mentioning that when you kick a soccer ball or shoot an arrow or fire a missile or throw a stone, it arcs up into the air and comes down again ~ following the path of a parabola.  That kind of visual might have helped.

 

It wasn’t obvious to me how signs, symbols, and substitutions join together to become a coherent idea. In algebra, X marks the spot. (Well, sometimes it’s N or Y, as Mr. Franklin liked to say.)  To me it was like a pile of puzzle pieces, gray side up, not all that interesting until I finally realized that they fit together to create something pretty intriguing.

 

The parabola made my eyes glaze over. But when I saw The Eiffel Tower?  I thought about wax paper.

Toni 6/16/17

 

 

 

 

3 thoughts on “WEEKLY PHOTO CHALLENGE: FOCUS

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