February 18, 2020

Key parts of computational thinking

breaking down a complex problem or system into smaller parts
Pattern Recognition
looking for similarities among and within problems
focusing on the important parts only, ignoring irrelevant detail
developing a step-by-step solution to the problem


  • Split a big problem into small parts
  • Using only a small set of words
  • Understand what is happening


Animate the letters of your name

  • Make a letter change color when you click it.
    • Choose a letter from the Sprite Library.
    • Choose a backdrop.
  • Make a letter turn when you click it.
  • Make a letter get bigger and then smaller.
  • Make a letter glide smoothly from place to place.

Scratch “language”

Data Elements

We store data in variables

These elements allow us to do things to variables

  • Set variable
  • Change variable

Control elements

  • Repeat N times

  • Repeat until …

  • If … then …

  • If … then … else …

Logical Operators

Notice that TRUE/FALSE blocks have a particular shape

Comparing two values always gives either TRUE or FALSE

Boolean Operators

George Boole (1815–1864) was an English mathematician, educator, philosopher and logician. He is best known as the author of The Laws of Thought which contains Boolean algebra.

Boolean Operators

They have diamond shape: logic

Question: How do they work?

Exercise: Make a cartoon

Try these in any order:

  • Say Something
  • Fly Around
  • Go Right and Left
  • Go Up and Down
  • Change Costumes
  • Glide from Here to There
  • Grow and Shrink
  • Change Backdrops