Presentation: Debugging a Healthy Morning Routine

Slide 1 of 7 · Settling starter · PSE / Well-being · Year 5

5 minutes

Debugging a Healthy Morning Routine

Cai is in Year 5 and lives in Cardigan. He keeps missing the school bus. He wrote an algorithm for his school morning, but it has bugs.

While the register is called: write your name, class and date on your worksheet. Then read Cai’s algorithm in section 2 of the stimulus sheet.

Starter question: Step 7 says “Brush teeth for 2 seconds.” What does the NHS say in section 4? What has gone wrong?

DCF: Data and computational thinking → Problem-solving and modelling No computers needed · work on your sheet

Slide 2 of 7 · Today’s brief and key words · PSE / Well-being · Year 5

3 minutes

Your brief: fix the algorithm so Cai catches the 08:10 bus

You will predict, find and fix the bugs, use a loop, turn the algorithm into a timetable, and then change it so Cai catches the bus and has a healthier start to the day.

Algorithm

A set of instructions in the right order to do a job.

Debug

Find and fix the mistakes (bugs) in an algorithm.

Loop

An instruction to repeat steps, for example Repeat 3 times: clap your hands. A loop makes an algorithm shorter.

LNF: Numeracy → Geometry and measurement → Measurement The coding words are in section 5 of the stimulus sheet

Slide 3 of 7 · Steps 1 and 2: predict and find the bugs · PSE / Well-being · Year 5

15 minutes

Step 1: predict · Step 2: find the 4 bugs

Step 1: before you calculate anything, will Cai catch the 08:10 bus? Why do you think that?

Step 2: there are 4 bugs. One is not wrong exactly, but it makes the algorithm longer than it needs to be.

Step	What is wrong?	How to fix it
2	He puts his shoes on before he gets dressed and puts his socks on.	Move “Put on shoes and coat” to after packing his bag, just before he walks to the stop.

Steps 1 and 2 on your worksheet · 15 minutes Look at the order of the steps, not just the words

Supply teacher script (no subject knowledge needed)

Say aloud: “Step 1, a few minutes: write your prediction and a reason, no working out yet. Then Step 2: find the 4 bugs. The first row on the board shows the shape: step number, what is wrong, how to fix it.”

Quick check, Step 1: any sensible prediction with a reason, for example he will miss the bus because 30 minutes of videos plus everything else is over an hour and he only has 70 minutes.

Quick check, Step 2: Step 2 (shoes before dressing), step 7 (2 seconds is far too short; brush for about 2 minutes like the NHS says), step 8 (he walks to the stop before packing his bag and filling his bottle; move it to the last step before END), step 9 (the same instruction written 4 times; use a loop: Repeat 4 times: put a book in the bag).

Slide 4 of 7 · Step 3: write the debugged algorithm · PSE / Well-being · Year 5

8 minutes

Step 3: write Cai’s algorithm again, with every bug fixed

Keep the 30 minutes of videos for now. Use a loop for the books. Start with START and finish with END.

Model start: 1. START: the alarm rings at 07:00. Get out of bed. 2. Go to the toilet, then wash hands and face. 3. Get dressed in school uniform and socks. 4. Watch videos on the tablet for 30 minutes.

The loop: Repeat 4 times: put a book in the bag.

Step 3 on your worksheet · 8 minutes 11 steps with the loop replacing 4 lines with 1

Slide 5 of 7 · Steps 4 and 5: timetable and change the plan · PSE / Well-being · Year 5

20 minutes

Step 4: make the timetable · Step 5: change the algorithm

Step 4: use the timing card. Each job starts when the one before it finishes. Then find the total and the time Cai reaches the stop.

Job	Minutes	Start	Finish
Toilet, then wash hands and face	5	07:00	07:05
Get dressed	10	07:05	07:15

Step 5: Cai wants to reach the stop by 08:05. Plan A: shorter videos. Plan B: earlier alarm. Then one change for his well-being.

Steps 4 and 5 on your worksheet · 20 minutes Books: 1 minute each, Cai needs 4 books

Supply teacher script (no subject knowledge needed)

Say aloud: “The first two rows are on the board. Fill in the rest in your debugged order. The loop counts as 4 minutes. Add up the minutes, write the total in hours and minutes, and work out how late Cai is. Then Step 5: work backwards from 08:05.”

Quick check, Step 4: videos 07:15 to 07:45, breakfast 07:45 to 08:00, teeth 08:00 to 08:02, books 08:02 to 08:06, bottle 08:06 to 08:08, shoes and coat 08:08 to 08:12, walk 08:12 to 08:19. Total 79 minutes = 1 hour 19 minutes. Cai reaches the stop at 08:19, 9 minutes after the 08:10 bus.

Quick check, Step 5: Plan A: 07:00 to 08:05 is 65 minutes; without videos the jobs take 79 minus 30 = 49 minutes; 65 minus 49 = 16 minutes of videos at most. Plan B: 08:05 back 1 hour 19 minutes is 06:46. (c) for example watch the videos after school instead; Cai would reach the stop at 07:49 and could eat breakfast slowly, and waking at 06:46 would mean less sleep.

Slide 6 of 7 · Self and partner check · PSE / Well-being · Year 5

3 minutes

Check your work against the success criteria

Swap worksheets with a partner or check your own. Tick each point in the box on your sheet once you can prove it is there.

I can find bugs in an algorithm and explain how to fix them.
I can use a loop to make repeated steps shorter.
I can make a timetable by adding minutes to times, and find how early or late something is.
I can change an algorithm to get a different outcome, and check it with times.

3 minutes · partner check Finished early? Try the IF step for Tuesday PE at the bottom of the sheet

Slide 7 of 7 · Plenary review · PSE / Well-being · Year 5

3 minutes

Quick-check answers before handing in

Check your main answers before your worksheets are collected.

Question	Correct answer
How long does the debugged routine take?	79 minutes, which is 1 hour 19 minutes.
When does Cai reach the bus stop, and does he catch the 08:10 bus?	08:19. He misses it by 9 minutes.
Plan A and Plan B to arrive by 08:05?	Videos cut to 16 minutes, or the alarm at 06:46.

Check your name and class are on your worksheet Leave stimulus sheets neat on the desk