Students write instructions for making a frosted cookie. The teacher follows their instructions exactly with ridiculous results. Students learn that computers only do exactly what you tell them to, and then English is imprecise.

Materials: gloves, cookies (4 packs from Dollar Store), frosting (4), knife in a ziplock bag, napkins, paper, pencils (9), large trash bag

Prep: Get approval to use food in class area. Lay out trash bag as a tablecloth and put your cookie supplies on it.

Intro: Computers will only do exactly what you tell them to. They aren’t smart enough to realize there is a problem. You have to be the smart one and give them good instructions! Imagine you were telling a person how to make a frosted cookie. You might say “put the frosting on the cookie” and they’d know what you meant. But if you told a computer that, you might get something like…(pick up the jar of frosting and put it on the package of cookies. Optionally, say “putting frosting on cookies” in a robotic voice). Is that what you want? So, we’re going to practice giving step-by-step instructions.

Pass out pencils and paper and give students a few minutes to write instructions. Put on gloves before touching the food. Have a student read their instructions and follow their instructions exactly.

For example:

• “Pick up the knife” -> pick the knife up without removing it from the ziplock bag
• “Stick the knife in the frosting” -> attempt to jam the knife through the lid of the frosting if they didn’t remove the lid first
• “Scoop out some frosting” -> assuming the lid is off, scoop it out with your hand

Give students time to revise their instructions, then repeat.

After a few minutes, tell the students that we’ve seen a few things: that we have to think about step-by-step instructions when we’re programming computers, that we’re going to be trying things and making mistakes and trying some more, and that the English language can be very unclear--so we’re going to be “talking” to computers in a language called Java!

Pass out frosted cookies.