Grid Algorithms


Using a small grid, students will guide their creature to an apple by giving step by step directions using arrows.

Rationale (Why we are doing this?)

Students will learn what an algorithm is: a list of steps that you can follow to finish a task.


  • 3×3 or 4×4 grid- multiple copies printed out for each student. See image 1 and 2 below.
  • Arrows printed out on paper. See image 3 below.
  • Scissors and glue.

Context and Background Knowledge

Students will need to have a very basic background with scissors and tape. It also helps to give a students a chance to see rocket design/features. This can be done through pictures, video, class discussions, etc. This can be made more complex when student start to compare actual rocket parts to the correlating parts of the their water rocket.

Curricular Connections (Competencies and Content)

Developing readiness and beginning to explore computational thinking.

Explore + Understand + Create (Key elements/Lesson Design/Format)

  1. At the front of the classroom, draw a large grid (3×3 or 4×4) on the whiteboard. In one box draw a small creature and in another box draw an apple. Show the students how to help the creature move through the grid to get the apple using arrows. Do some examples together as a class.
  2. Teach the word algorithm and explain how it connects to today’s lesson. Just as computers are programmed to follow step by step instructions, we are giving our monster step by step instructions to get to the food. An algorithm is a list of instructions.
  3. Afterwards, give each student a grid you have printed out and give them time to practice this skill independently or in pairs.
  4. Come back to the carpet and discuss the lesson: What was challenging, what did you like, what instructions would you give to a robot?


  • Use a larger grid.
  • Add obstacles to the grid that the monster must move around.
  • Put two or more apples on the grid and include “eat” as a direction along with the arrows.


  • Do students understand what an algorithm is?
  • Are they able to use arrows to give step by step instructions?


Images and ideas sourced from: