In the age of mp3s, most people have a lot of old CDs lying around. Instead of throwing them in the trash, though, you can put them to use in a way that's both eco-friendly and healthy. Thread the discs onto the ends of a thin metal rod and secure them in place with bolts to make a usable (and cool-looking) dumbbell. Tape up the middle of the rod to provide a comfortable grip, and you'll be all set for a workout.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.


Online Content Director: Suzanne LaBarre | Email
Senior Editor: Paul Adams | Email
Associate Editor: Dan Nosowitz | Email
Assistant Editor: Colin Lecher | Email
Assistant Editor: Rose Pastore | Email
Contributing Writers:
Rebecca Boyle | Email
Kelsey D. Atherton | Email
Francie Diep | Email
Shaunacy Ferro | Email
Good idea for my old CD's.
Better way to make sure you don't mess up the threads on the rod is to put the nut on before cutting, then if cutting messes up the threads you can just unscrew the nut and it will fix the threads on the way off.