Linkfest for Saturday, April 26

Partly I'm compiling these links for my own benefit, but some of this week's posts were pretty exciting. I hope you're out there enjoying them. Please let me know. Thanks.

• Varied, interleaved learning feels less effective, but is shown to be significantly more effective.
• Visualizing solutions to n-th degree algebraic equations using right-angle geometric paths. (I want to try to read this when I have more time and mental energy.)
• Mr. K describes how substitute teaching has made him a better teacher.
• Yakov Sinai models motion on a square pool table with a round cushion in the middle. He's proved that the ball will eventually hit every point on the table. This helps physicists understand gasses.
• Fawn's shopping contest - a way to practice percents (for discounts and tax) in a more challenging context.
• Nix the Tricks is a free ebook created by Tina Cardone with the help of dozens of math teachers online. Which 'tricks' are you attached to? Which make you cringe when your students mention them?
• A number of bloggers are answering some questions Grant Wiggins posed. Number one, why is division by zero undefined?
• Cathy O'Neill interviewed Fawn Nguyen on the math Common Core standards. Fawn is an optimist. I fear that the goodness she describes in the standards may be overpowered by the harm done with the endless testing, money for testing (instead of for teaching and learning), evaluations of schools and teachers determined by testing, etc.
• A game. Make a graph with the given number of edges at each node.
• Geoff's series of posts (especially number three on summer school with Jo Boaler, and number four on Chirstopher Danielson's hexagons) about the workshops he attended at the NCTM conference in New Orleans made me wish I could have been there.
• What do proofs with 5-year-olds look like? Rodi tells them, “I hear with my eyes and see with my ears.” And they work very hard to prove her wrong.
• I am dedicating Playing With Math: Stories from Math Circles, Homeschoolers, and Passionate Teachers to Seymour Papert.  You can get some nuggets of his by following The Daily Papert. From Wednesday: “You learn in the deepest way when something happens that makes you fall in love with a particular piece of knowledge. “ 
• When students make their own definitions...
• Mr, Honner, Solving Pallet Equations.
• I have not managed to solve the Robot Maze Puzzle. Can you?
• Leading into calculus, estimating areas.
• Parametric projectile motion simulated in Desmos.
• Are you required to have the standard you are teaching on the board? Mr. K describes why that sucks. Spoilers, anyone? And then Brooke Powers describes how helpful it is to share your bigger goals at the beginning of a unit. (I don't think my way of doing that would satisfy the folks hovering over high school teachers. Thank goodness I teach college.)

This one's not math, but it's too good not to mention: Researchers are analyzing similarities between the behavoir of ants and neurons.