Pie Lab teaching notes

About these notes

Pie Lab is a pie in 3D with two jobs for a program. The lattice top is woven by a rule: number the strips from 1, add the two numbers at a crossing, and an even sum means the strip going front to back is on top. The oven is run by rules the student writes as sentences: when something happens, do something, right away or after a wait.

It is written for grades 3 to 5 and the CSTA standards for algorithms and programming at that level: creating programs with sequences, events and conditionals (1B-AP-10), comparing algorithms for the same task (1B-AP-08), and testing and debugging (1B-AP-15). Rules are sentences of choice words, never typed code, which keeps it inside the grade 3 boundary of the 2026 standards.

One period

1. Look at the weave (5 minutes) Everyone opens the cherry pie. Ask what the strips do. Over, under, over. Click one crossing: the strip goes under, and the readout says some strip now goes over two in a row. Put them all back.
2. Find the rule (10 minutes) Open the Top tab and look at the grid. Strip 2 crosses strip 3: 2 + 3 = 5. Is that strip on top? Try three more crossings. Then choose My rule, read the sentence aloud, and change even to odd. Every crossing flips.
3. Bake by hand (5 minutes) Press Bake and take it out when it looks done. Most students get a red or white ribbon, or a burnt edge. Read what the judge said.
4. Write two rules (15 minutes) Oven tab, Add a rule: "When the edge is golden, right away put foil on the edge." Add another: "When the filling bubbles, wait 5 minutes, after that take it out." Bake and do not touch anything. Read the timeline: where did each rule happen?
5. Chase the blue (5 minutes) The judge says what kept the pie from the blue ribbon. Change one thing (the low rack helps a pale bottom) and bake again.
6. Exit question (5 minutes) Your foil rule happened at 21 minutes. The edge stayed golden. Did the rule happen again? Why not?

What students get wrong, and where the app answers it

The judge and the ribbons

Every pie that comes out is judged. A white ribbon is done in the middle with nothing ruined. A red ribbon adds a golden edge and a golden top. The blue ribbon also needs the pie out at just the right time, a bottom that is not pale (custard pies are not judged on the bottom), an edge and a top that match, and a weave with no strips out of place.

A burnt pie, one that bubbled over, one with a crack, or one raw in the middle gets no ribbon and an honest line about the pie: "The edge is charcoal." The judge never talks about the student. When a student shares a pie with no ribbon, Pie Lab asks for a better one first, so the gallery fills with good pies rather than funny bad ones.

• Cherry or apple: the low rack in a metal dish, and "When the filling bubbles, wait 5 minutes, after that take it out."
• Blueberry: the same, with the top brushed with egg. The cherry rule alone gets red or white.
• Pumpkin: "When the filling is set, right away take it out." Left in, the middle gets too hot and the top cracks.
• A glass dish never gets the blue in Pie Lab: a metal dish heats the bottom faster, and in glass the bottom is still pale when the filling is ready.

What the app simplifies, on purpose

• The oven is the app's own model. The causes are real ones, the times and colors are Pie Lab's own, and the app says so on the Oven tab and on the printed sheet. It is not a recipe and gives no amounts.
• In Pie Lab a fruit filling thickens after 5 minutes of bubbling. Real bakers often wait 5 to 10 minutes or more.
• A rule can only come true once here, because a crust never gets paler and the clock never runs backward. In block code a when block can run each time its event happens again.
• A pumpkin pie goes in the fridge after about 2 hours, because it is made with eggs and milk. The app's slice stops at the cooling.
• Four pies for now. The spec has more (pecan, lemon meringue, pot pie) for later.

Grades 3 to 5 and grades 6 to 8

The sheet, the puzzles and the setup

The sheet quotes the student's own pie: its strips and dough, the minute its first rule came true, and its ribbon. It cannot be handed in until the pie is baked and every question is answered, and it prints with a picture of the pie.

Eight puzzles. Four are choices built on the misconceptions above, where every wrong answer says why. Four are bakes the student's own pie has to meet: a blue ribbon cherry, a blueberry blue, a pumpkin with no crack, and a slice that holds its shape. They tick themselves when the pie does it.

Setup, in the app's header, chooses the grade level and the sheet's questions, takes up to ten of your own, and prints an answer key with the rules that win the blue for each pie. Save the project and hand it out as the starter.

Standards

• CSTA 1B-AP-10: create programs that include sequences, events, loops and conditionals (the oven rules, when the student writes them).
• CSTA 1B-AP-08: compare and refine multiple algorithms for the same task (woven, laid, two over two, and the student's own rule).
• CSTA 1B-AP-15: test and debug a program or algorithm (a rule that never happened, a pie that missed the blue).
• CSTA 1A-AP-08 and 1A-AP-11: algorithms for daily processes, and breaking a task into precise steps (the weave, one crossing at a time).
• CSTA 2026: E3-ALG-PS-01, E3-PRO-PD-04, E3-PRO-TR-08, E2-PRO-VD-05, E3-PRO-VD-06, E4-PRO-VD-06, E1-ALG-IM-03.
• Supports CCSS 2.OA.C.3: even and odd numbers. Connects to NGSS 2-PS1-4: heating causes changes that cannot be reversed.

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