April: in the streets!

Taxicab Geometry

I will be leading workshops on taxicab geometry at the AIM Math Teachers Circles next week. Here is the announcement:

Please join us for math and dinner with Henri Picciotto (www.mathedpage.org)!

The topic will be Taxicab Geometry. Many concepts in geometry depend on the idea of distance: the triangle inequality, the definition of a circle, the value of π, the properties of the perpendicular bisector, the geometric understanding of the parabola, etc. What happens to these concepts if we change the way we measure distance? In taxicab geometry, you can only move horizontally and vertically in the Cartesian plane, and therefore distance works very differently from the usual “shortest path” definition. In this workshop, we will explore the implications of taxicab distance. There are no prerequisites, other than curiosity and a willingness to experiment on graph paper.

Tuesday, April 11, 5-8 PM, AIM Math Teachers’ Circle, American Institute of Math (600 E. Brokaw Rd., San Jose) — RSVP

Thursday, April 13, 5-8 PM, Stanford Math Teachers’ Circle, Stanford University (Nora Suppes Hall 103, 224 Panama St) — RSVP

Driving directions and parking information for each meeting location can be found at the above links. Complimentary dinner and drinks will be provided at both locations.

I hope to see you there! If you can’t be there, work on it at home! The explorations will be largely based on Labs 9.1 and 9.6 from Geometry Labs, plus one additional problem: how would you define taxicab distance from a point to a line?


While taxicab geometry is inspired by theoretical streets, the March for Science and the People’s Climate March will take place in actual streets all over the country.

For a few decades now, science has been under attack from industry-funded “merchants of doubt“. Their strategy has been to challenge well-known, widely-accepted, and abundantly replicated scientific results with the bogus claim that “the jury is still out”. They have worked for the tobacco industry, for polluters, and for the fossil fuel industries. The media has unfortunately been gullible and/or complicit, and spread their message far and wide. One embarrassing and terrifying consequence is that, for example, the United States is the only country in the world where people think the research on climate change is inconclusive.
We are now seeing the catastrophic implications of this. Trump’s team is bent on reversing the already insufficient environmental protections that had been put in place by previous administrations. If they succeed, it will be a terrible blow to public health, and will have disastrous consequences for the planet. Moreover, they are planning to reduce the funding of federally-supported research on science, health, and the environment  at a time when we need it more than ever.
In other words, this is a crisis. It is the reason why I am including a political call to action in a math education blog. (Don’t worry, I’ll soon get back to the math.) 
I am planning to join other math people at the San Francisco March for Science on April 22, and again at the People’s Climate Movement March in Oakland on April 29. If you can, go to DC (Science | Climate.) If not, find a local march and join it (Science | Climate).
And don’t stop there! What can we do as math teachers? Can we develop curriculum ideas in defense of science, public health, and the environment? What can we do as citizens? The resistance possibilities are many, and resistance is definitely not futile. Citizen action has already helped to stop some of the worst initiatives emanating from the White House. If each of us finds a way to get involved we can help prevent the worst, and even push things forward.


[Apologies: I was not able to organize a math teachers’ contingent as I had hoped.]


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