Block coding lesson 5: Getting round walls
US version. US grades and US spelling. · UK version of this lesson
Myrtle cannot go through walls or off the grid. If a block would move her into a wall, Myrtle stops there and the rest of the program does not run. A complete 30-minute block coding lesson (Grades K–2), from Unit 2: Bugs and walls. Myrtle the Turtle runs right here in your browser – nothing to install.
- Time
- 30 minutes + 10 min homework
- Grade
- Grades K–2 (ages 5–8)
- You need
- A computer or tablet, squared paper and a pencil
- Graded
- Instantly, with explanations
For parents: how to use this lesson
You don't need to know anything about coding. The lesson explains each step on screen, the way Mr Babbage, our Head of Computing, likes it: watch Myrtle first, then have a go. Programs are made from blocks – no typing – and every answer is graded straight away.
- Before the screen: Build a maze with cushions and guide a toy round it with spoken blocks.
- Press Start the lesson below and watch the worked examples together. Press Run and say what each block does before Myrtle does it.
- Let your child do the practice on their own. When Myrtle goes the wrong way, that's a clue, not a failure – press Run again and watch which block it is on.
- Finish with the talk question: “What does Myrtle do when she bumps into a wall?”
- Later that day or the next day: the homework (10 minutes), then a practice test.
Watch out for
- Thinking Myrtle can go through a wall. Walls are solid. Plan a way round.
- Thinking the program carries on after a bump. A bump stops the program. Nothing after it happens.
Miss Lovelace's tip for home: ask your child to be Myrtle. Read out the blocks and let them walk it on the floor. If they can act it out, they understand it.
What your child will learn
Learning goal: plan a route round walls.
Success looks like
- I can plan a route round walls.
- I can say what happens when Myrtle bumps into a wall.
- I can fix a program that bumps.
Key words
wall · bump · route · obstacle
The big ideas (for the adult)
Myrtle cannot go through walls or off the grid. If a block would move her into a wall, Myrtle stops there and the rest of the program does not run.
When it bumps, look at the block it was on: that is where the route needs to change.
A worked example
move forward 1 turn left move forward 2
Press Start the lesson to watch the turtle run it.
The lesson, step by step
| Part | Time | How it is checked |
|---|---|---|
| Starter | 4 min | Graded by Classfern |
| Teach | 7 min | Watch, talk and try |
| Worked example and try it | 6 min | Graded by Classfern |
| Practice | 9 min | Graded by Classfern |
| Wrap up | 4 min | Graded by Classfern + self-check |
The lesson
It runs here on the page. No sign-up and no names – progress is kept only in this browser. Each visit picks a new mix of questions.
Homework
10 minutes: 4 questions – work out what Myrtle does, then build or fix a program – and a short reflection. New questions every time, all graded instantly. Away from the screen: build a maze with cushions and guide a toy round it with spoken blocks.
Practice tests
- Block Coding: Bugs and Walls Practice Test (Grades K–2)10 questions · graded instantly
- Block Coding: Mixed Practice Test (Grades K–5)15 questions · graded instantly
All computer science practice tests · All 18 block coding lessons
Curriculum
CSTA K–12 Computer Science Standards (2017), grades K–2: 1A-AP-11 – Break a problem's steps into a precise sequence of instructions; 1A-AP-14 – Find and fix errors in algorithms or programs with sequences and simple loops.
The standard codes are CSTA's; the descriptions are our own words.
Our lessons, blocks and questions are our own. They are not written or endorsed by any government department, testing agency or exam board.