field trip

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A group excursion for the purpose of firsthand observation, as to a museum, the woods, or a historic place.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A trip into the field.
• noun An educational trip.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a group excursion (to a museum or the woods or some historic place) for firsthand examination