Who is Karel?

Karel is a little robot who loves mazes and can move through them using just a handful of very simple commands such as go (make one step forward), left (turn 90 degrees left), right (turn 90 degrees right), get (collect an object from the ground) and put (place an object to the ground). He also can detect obstacles and collectible objects using the if-else statement, and repeat actions using the counting (repeat) and conditional (while) loops. He has a GPS device and can work with comparison symbols and Boolean variables. He can use numerical variables and text strings, custom commands and functions, Python lists, and even recursion. Yet the language is so simple that it feels like talking to the robot in plain English. The simplicity of the syntax allows the students to focus on the problem solving aspect of the course, without being frustrated by battling difficult syntax features of a real programming language.

What Does Karel Teach?

While solving mazes of gradually increasing complexity, students develop strong computational thinking skills and programming logic. This is something that they will need for any other programming language they will learn after Karel. They also learn how to type programs in a simplified Python language. They learn that failing of OK and how to step through their program and find the bug if the program does not work. The full Karel Coding course has 175 game levels. It is well structured. In Sections 1 – 2 students begin with writing simple programs using the elementary commands go, left, right, get and put. In Sections 3 – 5 they get used to recognizing repeating patterns and using loops. In Sections 6 – 25 students learn conditions, conditional (while) loops, variables, custom commands and functions, Python lists, recursion and more. At the end the self-paced course offers a series of programming challenges.

Solution Manuals

Solution Manuals

Karel Commands

Karel Commands

Extension Activities

Visit NCLab’s Free Apps to experiment with building your own mazes and games for Karel. In order to save the games and share them online, you will need to create a free user account in NCLab at nclab.com/sign-up/.

Additional Resources

Additional tutorial videos, textbooks, lesson plans, pacing guides, student journals and examples of real student work are available at the NCLab Resources page.

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I’m finished with my Hour of Code

Karel Coding – Hour of Code – Teacher Resources