The 7th graders had a test. It was a simple grammar thing--they had to identify the subject and the verb in various sentences. It didn't take them the whole period.
Then I was to put the key under the document camera and project it onto the board so the students could correct it.
Document cameras and projectors have become pretty standard in classrooms nowadays. I know how to turn the things on and diagnose most problems. So, when it came time to do the corrections, I didn't anticipate any problems.
The projector turned on. The document camera worked. But what got projected onto the board was a white blob. I tried to focus the document camera. Turned it off and back on. Tried to make the thing bigger. But no matter what I did, words did not appear on the screen.
(As I sit here and type this two days after the event, it now occurs to me that I didn't check to make sure the projector was in focus. *facepalm*)
Students came over to help, but they were as flummoxed as me.
After five minutes of this, I decided that the best way to do this was the old-fashioned way. By reading out the answers.
Ah well. At least it got done.