There are scanners built into the public printers (ps3a, ps3b, ps3c, ps4a, ps4b). These can be used to scan documents or images to PDF or TIFF format and send them via Email. These scanners are black and white only. Instructions are posted on the wall above the printers, and online at http://www.cs.umd.edu/faq/newprinters
There is also a scanner attached to the PC in AVW 4180. This is a full-color flatbed scanner. You need a Junkfood windows account to use this scanner. Contact staff@cs.umd.edu or visit AVW 4120 if you don't have access to this machine.
See http://www.cs.umd.edu/faq/scanner for detailed instructions on using the scanner in 4180.