Computer Science
Grade 2
20 min
Algorithm Challenge: The Perfect Tower
Students work in teams to create the most stable tower using limited materials and a predefined algorithm.
Tutorial Preview
1
Introduction & Learning Objectives
Learning Objectives
Follow a multi-step algorithm to build a tower.
Identify a repeating pattern (a loop).
Explain the sequence of their building steps.
Find and fix mistakes (debug) in a tower.
Use rule-based thinking to solve a problem.
Create their own simple algorithm for a new tower.
Have you ever built with blocks? π€ Let's learn the secret steps to build the perfect tower!
We will learn about algorithms. An algorithm is like a secret recipe. It helps us build amazing things every single time! π
Real-World Applications
Following a recipe to bake a cake π
Using LEGO instructions to build a spaceship π
Getting ready for school in the morning βοΈ
Playing a board game with rules π²
2
Key Concepts & Vocabulary
TermDefinitionExample
AlgorithmA list of steps to finish a task. It's like a plan! π1. Get a block. 2. Put it on the floor. 3. Get another block. 4. Put it on top.
SequenceThe order that you do the steps. First, then next, then last. ι ηͺYou put on your socks BEFORE you put on your shoes. That's a sequence!
LoopWhen you repeat steps over and over again. πClap your hands three times. The action 'clap' is in a loop!
PatternSomething that repeats in a way you can guess. π¨A tower with the colors Red, Blue, Red, Blue... follows a pattern.
DebugFinding and fixing a mistake. We call mistakes 'bugs'! πIf your tower falls, you debug by finding the wobbly block and fixing it.
RuleA special instruction you must always follow. π¦A rule could be: 'Only use square...
3
Core Syntax & Patterns
The Size Rule
Big blocks must go on the bottom. Small blocks must go on top.
Use this rule first to make your tower strong and not wobbly! πͺ
The Color Pattern Loop
Stack in this color order: π΄ Red, π‘ Yellow, π΅ Blue. Then repeat!
Follow this pattern over and over. This is your color loop. π
4 more steps in this tutorial
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Challenging
The code is: 'Repeat 2 times: [Add a Red block, Repeat 2 times: [Add a Blue block]]'. What is the final tower from bottom to top?
A.Red, Blue, Red, Blue
B.Red, Red, Blue, Blue
C.Red, Blue, Blue, Red
D.Red, Blue, Blue, Red, Blue, Blue
Challenging
The rule is 'Repeat 3 times: [Big, Small]'. Which tower has a bug because the loop ran the wrong number of times?
A.Tower 1: [Big, Small, Big, Small, Big, Small]
B.Tower 2: [Big, Big, Big, Small, Small, Small]
C.Tower 3: [Big, Small, Big, Small]
D.Tower 4: [Small, Big, Small, Big, Small, Big]
Challenging
If the Perfect Tower algorithm is [Big, Medium, Small], what algorithm would you write to build its 'mirror image' or 'upside-down' version?
A.[Big, Medium, Small]
B.[Small, Medium, Big]
C.[Medium, Small, Big]
D.[Big, Small, Medium]
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