Variables in Scratch

A variable is a “box” with a name, whose value can change while the program runs. It stores a number or text. In games, variables usually hold things like the score, lives left or the time.

In Scratch you create a variable in the Variables category with the “Make a Variable” button. Give it a meaningful name, for example score. The variable appears on the stage as a counter, so the player sees its current value.

The main blocks are: “set score to 0”, which gives the variable an exact value, and “change score by 1”, which changes it, here increasing it by 1 (with −1 it decreases). A game usually starts with “set score to 0”, otherwise the old value would stay.

An example is the game “Catch the apples”. Move the basket with the arrow keys, and while an apple falls use the blocks “if touching basket? then change score by 1”. As a result the score grows with every apple caught. A variable’s value can also be put into a “say” block.

Key takeaways

• A variable is a named place in memory whose value can change.
• “Set” gives it a value, and “change” increases or decreases it.
• A variable should have a meaningful name.
• A variable should be set to its starting value at the beginning of a game.