## Tuesday, October 6, 2020

### LOC Mystery Photo Contest - A Good Test of Search Strategies

At about this time last year the Library of Congress hosted a mystery photo contest. They're hosting another one right now. Just like last year's contest the challenge is to identify the people in twelve pictures pulled from the library's moving image section. Before you say, "just do a reverse image search" you should know that the LOC has already done that and not found any matches. That's what makes this contest so difficult. Just like last year's contest, this year's LOC Mystery Photo Contest doesn't offer any real prizes other than the satisfaction of being right.

Applications for Education
If you're looking for a difficult search challenge activity to use with your students, the LOC's Who Am I? Mystery Photo Contest could be just what you need. Students will have to string together as many clues as possible in order to get to arrive at an answer.

On a related note, Dan Russell's The Joy of Search is a must-read for anyone who wants to get better at using advanced search methods. I also offer course on teaching search strategies to students. You can access that course here

### Map Lessons from Mathigon

Last spring I wrote about Mathigon's Map Coloring Challenge. That's not the only map-based math lesson available from Mathigon. Mathigon's lesson on spheres, cones, and cylinders incorporates map projections.

In Surface Area of a Sphere Mathigon includes an interactive diagram that illustrates the problem that cartographers have when trying to create maps of the world. The interactive diagram shows four map projections and the areas of the map that are distorted by each projection. Students can click on each of the map projections to see a comparison of an area on the 2D map to the same area on a globe. Overall, it's a good way for students to see how two dimensional world maps can distort the size and scale of an area.

Mathigon's Map Coloring Challenge asks students to use as few colors as possible to color in all 50 U.S. states without having the same color touching two states at the same time. For example, if I color New Hampshire purple, I can't use purple on Vermont, Maine, New York, or Massachusetts but I could use purple on Pennsylvania.

On a related note the USGS offers a free map projections poster (link opens a PDF). You may also want to take a look at Projection Wizard as another tool for showing students how various projections distort the regions of the world.

Applications for Education
Years ago I did a hands-on lesson with students in which they used strips of paper to create a globe that was then laid flat so that they could see the difficulty in creating an accurate 2D map of the world. Mathigon's Surface Area of a Sphere accomplishes a similar goal in an online format as does the Projection Wizard site mentioned above.