Last week I received the following question: "A question of earth-shattering importance that occurred to me ... When and why was it customary for students to bring an apple for the teacher?"
He asked the question of me because he though this was a linguistic question. We have expressions such as, "an apple for your teacher." I speculated that giving an apple to the teacher was a supplement to their small salaries. That was incorrect.
As a crop apples began to be cultivated in the mid-19th century. It didn't take long for people to discover how to keep apples edible for many weeks after harvest. Apples became a convenient snack for school children. They were easy to carry and became a sweet ready-to-eat treat. Teachers even gave them out as rewards.
Eating apples did have one problem for teachers who wanted disciplined, silent classrooms, students couldn't eat them quietly. Apples snap when bitten. Look at this quote relating what went on with an apple in the classroom from The Ohio educational monthly, Volume 34 page 257 1885 “ A Bit of Experience” by R. M. Streeter, of Titusville, Pa.,
Now, I like apples; and I suppose I have done what that boy has just been doing a good many times in my life. I saw him when his head went into the desk; when that big bite left the apple I heard it, and I saw every eye in that neighborhood turn to me to see if I knew what was going on. From that day to this the rest of those schoolboys believe that I never knew about that apple being eaten.
Students would hide their heads and eat snacks. In order for teachers to prevent this noisy behavior, they would require the students to leave their apples on the teacher's desk. Students who ate apples in secret would also drop the apple cores on the floor or throw them against the walls causing a mess and a walking hazard. (see The R.I. schoolmaster: Volume 7 1861 Page 235.)
From this it is a small jump to bringing an apple for the teacher.