In this video, I walk through how I create my Race Car Repel science activity for my students. I use bright poster board, painter’s tape, and a Sharpie to design a reusable racetrack, then tape a bar ...

Editor’s Note: This article previously appeared in a different format as part of The Atlantic’s Notes section, retired in 2021. Refrigerator magnets are small, cheap, durable, colorful and come in a ...