When Xena strikes the bottles with a metal spoon, she causes the bottles and the water inside them to vibrate. The bottle with the most water makes the lowest-pitched sound. The bottle with the least ...

Want to play the xylophone but don’t want to learn how? [Rachad]’s automatic xylophone might be just the ticket. It uses homemade solenoids to play tunes under computer control. Think of it as ...