## Pick A Point

February 12th, 2014 by Dan Meyer

Here’s my favorite moment from a workshop in Spokane last week:

It’s about the quickest and most concise illustration I can offer of Guershon Harel’s necessity principle. The moment of need is brief, but really hard to miss. It sounds a lot like laughter.

**2014 Feb 19**. Christine Lenghaus adapts the interaction for naming angles:

I drew a large triangle and then lots of various sized ones inside it and asked the students to pick an acute angle. I asked a student to describe the one they were thinking about and then another student to come up and mark it! This lead to discussion on how best to label so that we both agree on which angle we were talking about. Gold!

**Featured Comment**

There’s an easy way to do this in Geogebra.

Open up blank Geogebra file, viewing only the Geometry window (no Algebra window).Click the point tool and make a bunch of points like in Dan’s video.

Then there is a small button AA with one A in black and the other in grey. This button shows and hides labels for all points.

on 12 Feb 2014 at 11:13 am1 ClaraWow. Now I just have to find these moments in the mundane and exploit them. Without any comment. I have students who would respond: why didn’t you put the points on there in the first place! Thank you!

on 12 Feb 2014 at 11:32 am2 William CareyAnother thing this beautifully highlights is that math is fundamentally about communication. We name points so we can talk about them, either with other people or with ourselves.

on 12 Feb 2014 at 10:39 pm3 Jeff NaslundThanks for the intellectual perturbation!

on 13 Feb 2014 at 5:10 pm4 Mike CaulfieldBeautiful!

on 13 Feb 2014 at 8:00 pm5 CarloAwesome!! What program did you use to make this?

on 13 Feb 2014 at 8:33 pm6 Dan MeyerJust Keynote for the two slides in class.

I made this video using Final Cut Pro.

on 15 Feb 2014 at 9:12 am7 Andrew StadelSimple.

Clean.

Effective.

Necessary.

I think you’re also creating a need for communication between students and for them to be as descriptive as possible while keeping each other accountable.

Great design.

on 17 Feb 2014 at 8:19 pm8 TomWith more time, it might be fun to name them by numbers first.

on 19 Feb 2014 at 10:24 am9 JeffLove the idea! I hated teaching this in geometry. One idea I would try out too: I have worked with students on developing mathematical basics/tools to solve other math problems. Instead of just picking a point and describing it as the end goal, what if you had them work on picking 2 points to put a line through (so that naming points is a mathematical necessity)? Then they would have to describe 2 points…almost battleship style? It could also lead into similar x-y coordinate plane activities too.

on 22 Feb 2014 at 2:57 pm10 Problematic Situations | To Accumulate a Rate --- Integrate![…] Dan Meyer pick-a-point […]

on 25 Feb 2014 at 6:18 pm11 Solid Gold | Five Twelve Thirteen[…] This post of Dan Meyer’s on the importance of intellectual need. […]

on 07 Mar 2014 at 2:29 pm12 Mastering Circles | Easing the Hurry Syndrome[…] have read and watched Dan Meyer talk about providing students an opportunity to recognize a need for labeling, a need for organizing by […]

on 28 Aug 2014 at 10:56 am13 Joel PattersonThere’s an easy way to do this in Geogebra.

Open up blank Geogebra file, viewing only the Geometry window (no Algebra window).

Click the point tool and make a bunch of points like in Dan’s video.

Then there is a small button AA with one A in black and the other in grey. This button shows and hides labels for all points.

on 28 Aug 2014 at 3:26 pm14 Dan Meyer@

Joel, great hack! Added it to the top post.