A 3D printer makes an object by squirting out a tiny filament of hot plastic, adding one layer at a time. That’s why it’s called additive manufacturing. You send the printer a computer file that’s a 3D model of something — an iPod case, a bike part, your head — then it prints out the object for you. These machines are becoming affordable for schools, labs, libraries, and families, and there’s lots of software out there for creating 3D files to print.

When you’re done making your 3D model, you can take it to a makerspace where they have a 3D printer, or you can send it out to a service and they’ll print it and mail it right to your home. We printed our heads on an Ultimaker printer, using Cura as the printer software. It was easy!

Imagine what else you could 3D-print with these tools. Instead of printing your head, why not replicas of buildings or sculptures at an art museum? Or you