Points, Lines, and Planes, OH MY!

Full disclaimer:  This lesson is not my own!  A colleague from another school in our district told me about it, and then modeled it for us at our Back to School District-wide PD.  I was SO excited to try it!!  With good reason, too – it was amazing!!

So the lesson starts off with guided notes (linked at the bottom).  These aren’t anything new, it just happens to be what my colleague used, so I used it too.  We filled out the “undefined terms” section, then I passed out the playdough.

First I told them to make a point.  We went around and looked at all the points created.  Most students made a ball…others made shapes WITH a point. So that was our first discussion.  Then we filled in the guided notes on point.

Next was a line.  When I instructed them to make a line, every single one of them did the exact same thing… rolled a playdough snake.  And then I said, “I’m still waiting to see some lines.  I don’t see any lines…” It only took a little student-led discussion for them to figure out that I wanted arrows on the end of the lines.  This led to discussion about lines and the guided notes.  I ad-libbed a bunch of knowledge about lines, just like I normally would.

Next we talked about planes, did the notes, etc.  I told them they could think of their desktop as a plane.

They did not previously know the definition of collinear, but they worked together to figure it out. And they did it without any instruction from me!  All I did was instruct them to create two points that are collinear.  THEN the fun started.  I asked them to create two points that were NOT collinear.  We know it’s impossible, but boy did they try!  It was so funny!  And I walked around with meter stick and made a line with it through each of their two points.  “Nope, they are collinear…Nope, those are collinear…”  It didn’t take long for them to realize that any two points make a line.  Next we did the same for coplanar.  And creating three points that are not coplanar.  One student even went so far as to stick a point on my bulletin board halfway across the room.  And I still made a plane through them! (2nd picture below)

I knew this lesson was a winner when one student who was really confused about the plane started moving her third point around with her paper.  She exclaimed “Oh!  I get it!”  (1st picture below)  I don’t think I’ve ever had my students be able to really GET points, lines, and planes this well on the first day.

We only got through line segments today, we will continue the rest tomorrow, but I am calling this a win!

I am excited to figure out how else to use the play dough.  I know I will use play dough and dental floss to show cross sections, but please share if you have any more ideas!!

Here is the file for the worksheet I used:

Points Lines and Planes with PlayDough

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