dipsticking
n.—Gloss: taking random samples or randomly choosing people to question. «One recent morning, Ms. Cascio asked several students in succession to explain the logic of their answer to the same question—and, “Uh, yeah, I agree with Yasamin and Josh” just wouldn’t do. “It’s called dipsticking,” Ms. Cascio said. “It’s really important to make sure the kids are picking this information up, and so I ask, Is this clear to you? Do you really understand it? and I won’t go on until I get a positive, satisfying answer.”» —“In Science Classrooms, a Blast of Fresh O2” by Natalie Angier New York Times Oct. 30, 2007. (source: Double-Tongued Dictionary)
Further reading
Amid court-ordered busing in the 1970s, a middle-school teacher tried to distract her nervous students on the first day of class with this strange assignment: find a monarch caterpillar. The result? A memorable lesson in the miracle of metamorphosis...
There was a time when William Shakespeare was just another little seven-year-old in school. Classes in his day were demanding — and all in Latin. A new book argues that this rigorous curriculum actually nurtured the creativity that later flourished...
I have heard the term used commonly within demeaning phrases. The person is only as smart as what is directly in front of their face. Does not connect any other background or known information with what is facing them in current time/place.
I do like the small irony of this definition from MW’s Open Dictionary:
“dipstick (other) : A stuipd or dum person”
http://www3.merriam-webster.com/opendictionary/newword_display_recent.php?id=4705