Wednesday, November 20, 2013

Trigonometry INB

So it has been A LONG time since I posted on this blog.  Almost every day I think of things I would love to write about but just don't have the time to sit down and do it.  

Today though, I thought I would start my posts about my Trigonometry INB.  I don't know that I do an INB in the way in which it is fully theorized to be, but I LOVE the way I do it and it works for me and my classes. :)

Today I was teaching an application of radian measure - Length of a chord, to my trigonometry class.  When I drew in the central angle for the chord, one of my students loudly asked, "WHY does EVERYTHING come back to triangles??"  Another student replied, "Because a triangle is the perfect shape. "  In the true manner of a teachable moment, I felt the need to explain why I agree that a triangle is a perfect, useful, shape......but in a fun, hands on way!

I pulled out a pipe cleaner and a straw from my closet (I realize most math classrooms don't have these items hanging around, but I am called the "mathbooker" here are school so I have LOTS of craft items in my closet. :)  )

You cut the straw into three pieces that would form a triangle, (this is a great time to remind students that not all three lengths will necessary make a triangle either). 

Put the pieces of the straw on the pipe cleaner. 

Form the triangle. Twist the pipe cleaner ends together and cut off the excess.

I also do this again, but I cut the straw into 4 pieces to make a quadrilateral. 

We then compared the strength of the shapes.  It took a lot of pressure to get the triangle to bend.  And it didn't bend at the vertices, it bent on a side b/c the straw gave way. 

Since this was a trig class and not geometry, we had a GREAT discussion about the uses of triangles, and why they are used for support on bridges, etc.

Going back to my INB....I have a student who is a little crafty (she loves the INB), and proceeded to use her triangle to form the angle in her arc for her lesson on chords.  How creative was she?  Of course, I took a picture, and I now know that this is going into my own personal INB for next year and maybe I can lead the discussion to get the students to ask these questions again. :)

 Just thought I'd share! :)  I'll try to get more pics of my INB's up soon.