Scratch Coding · Grade 5 · Chapter 6

Scratch Variables: Scorekeepers & Timers

Using computer memory to track game scores, lives, levels, and countdown timers.

Learning Goals

What We'll Build Today

GOAL 1

Variables Concept

Understand variables as labeled storage containers in computer memory.

GOAL 2

Set vs Change

Master resetting variables at game start and modifying them during gameplay.

GOAL 3

Game Timers & Lives

Build working scoreboards, 30-second timers, and player health bars.

Real-World Memory

How We Keep Score in Real Life

Think of a basketball game: the stadium scoreboard holds Home Team Score and Game Clock. Every time a basket is made, the score changes!

Discussion: What would happen in a video game if the computer couldn't remember your score or health?

Story Time

Noah's Unending Rocket Game

Noah built a super cool arcade game where a rocket dodges asteroids. But players complained: "There's no score, no health bar, and no way to know if you're winning!"

Noah realized he needed a container in Scratch to store points and count down seconds!

Core Concept

What is a Variable?

A Variable is a labeled box in computer memory that stores a piece of information (like a number or string) that can change over time.

      Variable Name: [ score ]

      Current Value: 15

      Operation: change [ score ] by (1) ➔ New Value: 16

Visual Flow

The 4 Stages of a Variable

1

Create

Make a new variable in Scratch (e.g. Score).

2

Initialize

Set starting value (e.g. set score to 0 at flag click).

3

Update

Add/subtract points during game events.

4

Check

Use in conditionals (e.g. if score > 10 win!).

Scratch Block Distinctions

Set Variable vs. Change Variable

📌 set [score v] to (0)

OVERWRITES whatever value was inside the box with a brand new exact value.

Used for: Initializing at game start or resetting stats.

➕ change [score v] by (1)

ADDS (or subtracts) a value to the current amount inside the box.

Used for: Scoring points (+1) or taking damage (-1).

Code Example

Building a Coin Collection Scorekeeper

Here is how a coin sprite increases the player's score whenever collected:

      when green flag clicked

      set [score v] to (0) // Initialize!

      forever {

        if <touching [Player v]?> then {

          change [score v] by (10)

          play sound [Coin v] until done

          go to [random position v]

        }

      }

Game Mechanics

Building a 30-Second Countdown Timer

Creating a custom countdown timer variable in Scratch:

      when green flag clicked

      set [timer v] to (30)

      repeat until <timer = 0> {

        wait (1) seconds

        change [timer v] by (-1)

      }

      broadcast [Game Over v]

Player Stats

Building a 3-Lives System

1. Initialization

when flag clicked ➔ set [lives v] to (3)

2. Collision Damage

if ➔ change [lives v] by (-1), wait 1 sec

Debunking Myths

The Forgotten Initialization Bug

Bug: You play a game, score 25 points, and lose. You click Green Flag to play again... but your score STILL starts at 25 points!

Fix: You must ALWAYS put set [score v] to (0) right under when green flag clicked!

Smartboard Voting

Trace the Variable!

Look at this code:
set [score v] to (10) ➔ change [score v] by (5) ➔ set [score v] to (2)
What is the final value of score?

Option A: 17

Option B: 2

Vote: Thumbs UP for Option A, Thumbs DOWN for Option B!

Spot the Bug

Why Did the Score Jump to 10,000?

forever [ if then change [score v] by (1) ]
The player touched the coin for half a second and gained 500 points instantly!

Discussion: Why did the score rocket up so fast? (Hint: Missing hide or wait block after scoring!)

Think-Pair-Share

Multiplier Power-Up Logic

In video games, grabbing a Star gives double points (2x multiplier) for 10 seconds!

Partner Task: How would you use a variable named pointsPerCoin to handle 1 point normally vs 2 points during double power-up?

Guided Practice

Building Game Victory Logic

Let's build a win-check script together on the smartboard!

      when green flag clicked

      forever {

        if <score >= 50> then {

          say [YOU WIN! HIGH SCORE!] for (3) seconds

          stop [all v]

        }

      }

Hands-on Challenge

Clicker Game Challenge

Mission: Create a Scratch Clicker Game! Clicking the Cookie sprite increases Cookies by +1. At 20 cookies, unlock a second sprite that auto-clicks +1 per second!

Variables needed: Cookies and AutoClickers.

Quick Check · Question 1

Which block correctly adds 1 point to your score when you collect a gem?

Aset [score v] to (1)

Bchange [score v] by (1)

Cshow variable [score v]

Dmove [score v] steps

Click to reveal answer

Quick Check · Question 2

What happens if you forget to reset `set [score v] to (0)` at the start of a new game?

AThe game will not start

BThe player's old score from the previous game remains on screen

CThe score turns into a negative number

DScratch deletes the variable automatically