In this week’s issue: George Packer on the McChrystal debacle; Ken Auletta on Afghanistan’s first media mogul; Tad Friend on Steve Carell; Charlayne Hunter-Gault on Jacob Zuma; Rebecca Mead on playgrounds; James Surowiecki on financial illiteracy; Sasha Frere-Jones on Robyn; James Wood on David Mitchell; Peter Schjeldahl on Charles Burchfield; David Denby on “Knight and Day” and “Winter’s Bone”; fiction by Sarah Shun-lien Bynum; and more:

Microwave ovens use a particular microwave frequency to excite molecules of water. Since water is present in lots of food and drink, this means that microwaves heat up lots of useful stuff – and they do it quickly. The fact that microwaves are now readily available to most of us in the western world and they are only a few centimetres in length, means that you can measure the speed of light in your very own home.

Measure the Speed of Light Using Your Microwave | Orbiting Frog