Visualizations: Algorithm

• Peanut butter and Jelly
  [This is due to a teacher from the States, I neglected to write down her name, if she is reading this: please let me know so that I can attribute it to you!]
  Props: Jar of Peanut butter, Jar of Jelly, Butter, Loaf of sliced Bread, knife, paper towels
  Description: Ask the students to help you make a peanut butter and jelly sandwich. Everyone knows how to make one! Your job is to do exactly what they say, that is, to misinterpret the statements that have multiple meaning. For example: If a student says "Butter the bread" then butter the bread still inside the bag using your fingers! Once you get to the point of having a slice with peanut butter on it and a student says "Put it down", then you put it down with the peanut butter side down. Makes an awful mess, they are very interested, and will remember this for a very long time! Develop the properties of an algorithm after wiping up the mess.

  Lynn Andrea Stein, Professor at MIT, uses the Peanut-Butter-and- jelly Model for describing sequential programming in her "Rethinking CS101"

• Marionette
  Since people don't know what a peanut butter and jelly sandwich is here in Germany, I use a marionette (an "absent minded professor" I once found in a toy store!) instead. I set it on the table, and ask the students to help me get the professor off the table and walk him to the door. I misinterpret all that they say, it is interesting, but not quite as drastic as above. They remember it for many semesters, although some students who already thought that they could program found it silly.