Computer Science
Grade 2
20 min
Drawing Algorithms
Students write instructions for drawing a simple picture. Focus on spatial reasoning and step-by-step execution.
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1
Introduction & Learning Objectives
Learning Objectives
Define an algorithm as a set of steps.
Follow a simple drawing algorithm to create a shape.
Write a sequence of instructions to draw a simple picture.
Identify a repeating pattern (a loop) in a drawing algorithm.
Find and fix a simple mistake (a bug) in a drawing algorithm.
Create their own algorithm for a simple shape.
Have you ever wanted to teach a robot to draw? 🤖 Let's learn how!
We will learn how to write step-by-step instructions, called algorithms. These instructions tell a computer or robot exactly what to draw. It's like a secret code for making pictures! 🎨
Real-World Applications
Telling a video game character how to move 🎮
Making a drawing on a tablet or computer ✍️
Programming a robot to build things 🏗️
Creating animat...
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Key Concepts & Vocabulary
TermDefinitionExample
AlgorithmA list of steps to finish a task. Like a recipe for drawing! 📜To draw a smiley face: 1. Draw a big circle. 2. Draw two small circles for eyes. 3. Draw a curve for the mouth.
InstructionOne single step in your algorithm. It's one command. ☝️A single instruction could be 'Move forward one square'.
SequenceThe order of your instructions. The steps must be in the right order. 🔢You must draw the square's lines *before* you color it in.
LoopRepeating a set of instructions over and over. 🔁To draw a square, you REPEAT this 4 times: [Draw a line, then turn right].
BugA mistake in your algorithm that makes it not work. Oops! 🐞Your instructions say to draw 3 sides of a square instead of 4.
DebuggingFinding and fixing the bugs in your algorithm....
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Core Syntax & Patterns
The Arrow Commands
➡️ (Move Right), ⬅️ (Move Left), ⬆️ (Move Up), ⬇️ (Move Down)
Use these arrows as instructions to move your pencil one square on grid paper.
The Square Loop Pattern
REPEAT 4 TIMES: [➡️, ⬇️, ⬅️, ⬆️]
This is a fast way to write instructions for a square. It saves you from writing lots of steps.
The Pen Up / Pen Down Command
🖊️ (Pen Down), ✋ (Pen Up)
Use 'Pen Down' to start drawing and 'Pen Up' to move without drawing a line.
4 more steps in this tutorial
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Challenging
A robot's code to draw a ladder is: 'Draw line right. Move down. Draw line right. Move down. Draw line right.' How can you make this code shorter using a loop?
A.Repeat 3 times: [Draw line right. Move down.]
B.Repeat 2 times: [Draw line right.]
C.Draw one very long line right
D.You can't make it shorter
Challenging
The algorithm for a square is 'Repeat 4 times: [Draw side, Turn]'. To draw a triangle, you would change 'Repeat 4 times' to 'Repeat 3 times'. What would you change to draw a hexagon (6 sides)?
A.Repeat 3 times
B.Repeat 4 times
C.Repeat 5 times
D.Repeat 6 times
Challenging
To tell a robot to draw a simple stick figure 🧍, what is the BEST order of algorithms?
A.Draw head, draw body, draw arms, draw legs
B.Draw arms, draw legs, draw body, draw head
C.Draw legs, draw head, draw arms, draw body
D.Draw body, draw arms, draw head, draw legs
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