Help the robot reach the battery
Put move and turn blocks in order so a robot crosses a 5 × 5 grid to its battery. Run a broken plan to find the block where it bumps into a wall, fix it, and then find the shortest plan.
Core concept
An algorithm is a list of exact steps done in order; changing the order or one step changes the result, and debugging means finding the step where the plan breaks
Topic: Computational thinking
An algorithm: A list of clear steps that solves a problem, like a recipe. All key words is a list of steps that solves a problem, like a recipe or the directions to a friend's house. A computer follows the steps exactly and in order: it never guesses what you meant. Here a robot understands only three blocks: move forward one square, turn left and turn right. A turn does not move the robot; it only changes the way it faces. If one block is wrong or in the wrong place, the robot ends up somewhere else, or bumps into a wall. Finding that block and fixing it is called debugging.
What you will learn
- Explain what an algorithm is and why the order of steps matters.
- Predict where a robot ends after a short list of blocks.
- Find the block where a plan breaks and fix it (debugging).
- Compare plans and find a shorter one.
Before you start
- Know left and right, and the four directions north, east, south and west.
Materials
- A notebook and a pencil to draw the grid
Equipment
- None
Procedure
- Run the robot's first plan and see where it bumps into a wall.
- Build a new plan that reaches the battery, and run it.
- Make the plan as short as you can.
- Answer the practice challenges.