Lesson 10: Loops with Harvester


Building on the concept of repeating instructions from "Happy Loops," this stage will have students using loops to pick corn more efficiently on Code.org.


In this lesson, students will be learning more about loops and how to implement them in Blockly code. Using loops is an important skill in programming because manually repeating commands is tedious and inefficient. With the Code.org puzzles, students will learn to add instructions to existing loops, gather repeated code into loops, and recognize patterns that need to be looped.


Warm Up (10 min)

Bridging Activity - Loops (10 min)

Main Activity (30 min)

Wrap Up (5 - 10 min)

Extended Learning

View on Code Studio


Students will be able to:

  • Identify the benefits of using a loop structure instead of manual repetition.
  • Break down a long sequence of instructions into the smallest repeatable sequence possible.
  • Create a program for a given task which loops a sequence of commands.
  • Employ a combination of sequential and looped commands to reach the end of a maze.



Heads Up! Please make a copy of any documents you plan to share with students.

For the Teachers

For the Students


  • Loop - The action of doing something over and over again.
  • Repeat - To do something again.


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Teaching Guide

Warm Up (10 min)


Review the Happy Loops activity with your students:

  • What are loops?
  • Why do we use them?

Bridging Activity - Loops (10 min)

Choose one of the following to do with your class:

Teacher Tip:

If you predict that your students will have trouble with the idea of using repeat loops to not only move, but also pick corn, you can introduce this idea in the Bridging Activity. This will help students understand that loops can have many different uses.

Unplugged Activity Using Paper Blocks

Select an empty Flurb map from the Happy Map Cards - Worksheet and give students Unplugged Blockly Blocks (Grades K-1) - Manipulatives prefilled with the collect command, a repeat loop, and the cardinal commands like E → (East) and W ← (West). Now, have the students program the Flurb from their desks using the paper Blockly blocks to get the Flurbs to collect the fruit. Make sure that they understand that the blocks need to go from top to bottom and they all need to touch!

Previewing Online Puzzles as a Class

Pull a puzzle from the corresponding online puzzles. We recommend puzzle 6. Using arrows from the Happy Map Game Pieces - Manipulatives and Happy Map Game Pieces Bonus Pack - Manipulatives, have students lay out a pattern that they think will get the Harvester to pick all the corn. Ask the students to share. See how many other students had the same answer!

Main Activity (30 min)

Course A Online Puzzles 2018 - Website

As students work through the puzzles, see if they can figure out how many blocks they use with a loop vs. without a loop.

Wrap Up (5 - 10 min)


Having students write about what they learned, why it’s useful, and how they feel about it can help solidify any knowledge they obtained today and build a review sheet for them to look to in the future.

Journal Prompts:

  • What was today’s lesson about?
  • Draw one of the Feeling Faces - Emotion Images that shows how you felt about today's lesson in the corner of your journal page.
  • How did loops make your program easier to write?
  • Draw something that uses loops.

Extended Learning

So Moving

  • Give the students pictures of actions or dance moves that they can do.
    • Have students arrange moves and add loops to choreograph their own dance.
  • Share the dances with the rest of the class.

Connect It Back

  • Find some YouTube videos of popular dances that repeat themselves.
  • Can your class find the loops?
  • Try the same thing with songs!

Standards Alignment

View full course alignment

CSTA K-12 Computer Science Standards (2017)

AP - Algorithms & Programming
  • 1A-AP-09 - Model the way programs store and manipulate data by using numbers or other symbols to represent information.
  • 1A-AP-10 - Develop programs with sequences and simple loops, to express ideas or address a problem.
  • 1A-AP-11 - Decompose (break down) the steps needed to solve a problem into a precise sequence of instructions.
  • 1A-AP-14 - Debug (identify and fix) errors in an algorithm or program that includes sequences and simple loops.

Cross-curricular Opportunities

This list represents opportunities in this lesson to support standards in other content areas.

Common Core English Language Arts Standards

L - Language
  • K.L.6 - Use words and phrases acquired through conversations, reading and being read to, and responding to texts.
SL - Speaking & Listening
  • K.SL.1 - Participate in collaborative conversations with diverse partners about kindergarten topics and texts with peers and adults in small and larger groups.
  • K.SL.2 - Confirm understanding of a text read aloud or information presented orally or through other media by asking and answering questions about key details and requesting clarification if something is not understood.
  • K.SL.5 - Add drawings or other visual displays to descriptions as desired to provide additional detail.

Common Core Math Standards

G - Geometry
  • K.G.1 - Describe objects in the environment using names of shapes, and describe the relative positions of these objects using terms such as above, below, beside, in front of, behind, and next to.
MP - Math Practices
  • MP.1 - Make sense of problems and persevere in solving them
  • MP.2 - Reason abstractly and quantitatively
  • MP.4 - Model with mathematics
  • MP.5 - Use appropriate tools strategically
  • MP.6 - Attend to precision
  • MP.7 - Look for and make use of structure
  • MP.8 - Look for and express regularity in repeated reasoning

Next Generation Science Standards

ETS - Engineering in the Sciences
ETS1 - Engineering Design
  • K-2-ETS1-1 - Ask questions, make observations, and gather information about a situation people want to change to define a simple problem that can be solved through the development of a new or improved object or tool.
  • K-2-ETS1-2 - Develop a simple sketch, drawing, or physical model to illustrate how the shape of an object helps it function as needed to solve a given problem.