The lesson plan wasn't very specific. I was to assign some work from the end of a gases chapter. Um, okay...
From this clue and others in the lesson plan, I was fairly certain that the teacher had some sort of unexpected event, and he didn't have a textbook at home from which to choose problems. I know enough chemistry to wing it, so I found the first gases chapter and looked up the problems.
But how many to assign? The teacher didn't specify. I looked over the problems. Fourteen seemed a reasonable number. I figured I could finish them in the time allotted.
Then again, this is my subject. (Well, physics, not chemistry, but the problem solving skills are similar.) Was I overestimating their skills? How many problems would the teacher assign? What would be considered reasonable?
It's easier when I can just tell a class that the teacher gave them the work, and if they have any complaints to direct them to him. I planned to bluff and let them think that the assignment came directly from their teacher.
I wrote the assignment on the board. The class said it was a bit long. I relented and took away half the problems.
They finished in 20 minutes.
Sigh. I should have gone with my first instinct.
At least they were the kind of students who pulled out other work when they finished their chemistry assignment. It could have been worse. And then for the physics classes (the teacher had both chemistry and physics periods), I made sure to go with my first instinct for number of problems.