Why a Longer Coding Lesson Taught My Student Less

Last updated: August 2026

A longer coding lesson does not reliably teach more, and in July I have the two sessions to prove it. With Cameron, 15, one lesson ran about 55 minutes, produced three files, covered roughly twelve distinct concepts, and every one of them landed. The next lesson ran about 62 minutes, produced two files, covered fewer concepts, and midway through I said out loud that I did not think any of it was getting through.

Seven extra minutes, less learning. The cause was not difficulty, pace, or the student. It was that one sub-topic I had planned as a five minute warm up turned into a seventeen minute drill and quietly became the whole lesson.

Key Takeaways

• The shorter session covered twelve concepts successfully. The longer one covered fewer and left the main topic sharing the room.
• A seventeen minute detour intended as a brief motivating example became the session's main event.
• Concept density, not session length, is the variable that determines how much a student retains.
• The strongest sequence of the month worked because the difficulty was named out loud before it was attempted.
• The fix is to keep the motivating example small enough that it cannot compete with the topic it is introducing.

Table of Contents

• The Two Sessions
• What Made the Shorter One Work
• How the Longer One Went Wrong
• Why This Happens to Good Lesson Plans
• What I Changed
• What This Means for Choosing Lesson Length
• Frequently Asked Questions
• The Bottom Line

The Two Sessions

Cameron has been with me for more than 40 hours. He is a strong student, he builds a 2D fighting game in his own time, and he is not someone who struggles with the material in general.

	Session one	Session two
Length	~55 minutes	~62 minutes
Topic	Finishing conditional logic	Starting loops
Files produced	3	2
Distinct concepts	~12	Fewer, and one dominated
Outcome	All landed, hardest challenge solved and explained back	Main concept landed late, a long stretch of "I don't know"

Same student, same tutor, one week apart, opposite results.

What Made the Shorter One Work

The first session closed out conditional logic. The centrepiece was a challenge I genuinely find awkward myself: take a piece of logic written with "and" and reproduce exactly the same behaviour using "or" instead.

The scaffold is the part worth keeping.

1. Swap the operator and watch it break. No explanation first. Just change "and" to "or", run it, and see wrong answers come out.
2. Work out why it is wrong. With "or", satisfying a single condition is enough to let a value through, so values that should fail get accepted.
3. Invert the whole idea. Instead of describing the acceptable range, describe the unacceptable one. Below the minimum or above the maximum means stop.
4. Verify against edge cases, predicting before running. Pick values on both sides and in the middle, say out loud what should happen, then run it.

That is one of De Morgan's laws in practice, taught without ever using the name. Cameron got there, and more importantly he could explain the reasoning back afterwards.

One detail I think did most of the work: before we started I told him plainly that I find this one hard too. That gave him permission to struggle rather than treating slow progress as evidence he was failing. He had also never seen a truth table before, in school or anywhere else, so this doubled as a maths concept he will meet again later.

The rest of the session moved briskly through smaller ideas: why an else branch cannot be empty, reading an actual error message aloud and diagnosing it himself rather than being told the answer, chained comparisons, and the idea that values themselves can be true or false rather than only comparisons between them. Twelve concepts, all in under an hour, all retained.

How the Longer One Went Wrong

The second session opened the loops topic. My plan was sound on paper: motivate loops with a real problem rather than an abstract one. Take a messy string of data with numbers and separators mixed together, show that pulling the pieces out by position is fragile, and let the loop arrive as the obvious better answer.

Getting to "pulling pieces out by position is fragile" required reviewing how you extract sections of text by position. That review was meant to take about five minutes.

It took roughly seventeen, and Cameron said "I don't know" repeatedly through it. Partway through I told him I felt like nothing was landing, which was an accurate read.

By the time we reached the actual topic, most of the session was gone and his attention had been spent on a warm up. The loop concept did land in the end, along with the pattern of building up a result piece by piece as you iterate, and reading the documentation for a function by hovering over it rather than guessing, which is a habit worth more than the function itself. The Python documentation for string methods is exactly the kind of reference I want a student reaching for unprompted.

But it landed into a tired student in the last third of a lesson, rather than into a fresh one at the start.

Why This Happens to Good Lesson Plans

I want to be fair to the plan, because the instinct behind it was right. Motivating an abstract tool with a concrete problem is good teaching. Reviewing earlier material inside new material is good teaching. Neither of those was the mistake.

The mistake was that the motivating example was harder than the thing it was motivating.

Extracting text by position, with a start, a stop, and a step, and reasoning about which characters come out, is genuinely more demanding than understanding that a loop repeats an action once per item. So the warm up was uphill and the destination was downhill, which is backwards. A motivating example has to be cheap. The moment it costs more than the concept, it stops being an on-ramp and becomes a competing lesson.

The second contributor was that I kept going. Each individual step of the review was reasonable, and at no point was there an obvious place to stop. That is how seventeen minutes happens without anyone deciding it should.

What I Changed

Three things, and they generalise beyond this topic.

Cap the warm up before the lesson starts. If the motivating example has not landed in five minutes, abandon it and assert the conclusion instead. "Doing this by position breaks easily, take my word for it, here is the better way" costs one sentence and buys back twelve minutes.

Make the example simpler than the concept, deliberately. I could have used a much shorter and cleaner piece of data. The point was that position based extraction is brittle, and that point does not need a hard example to make it.

Watch for repeated "I don't know" as a stop signal, not a difficulty signal. My instinct in the moment was that he needed more practice. What he actually needed was for me to move on. Repeated uncertainty in a warm up means the warm up has failed, not that the student needs more of it.

What This Means for Choosing Lesson Length

Parents ask me fairly often whether a longer session would help, usually when progress feels slow. My honest answer, after 20 years and more than 200 students, and these two sessions are why, is that length is close to the least important variable.

What matters is how many distinct new ideas a session tries to introduce and whether any single one is allowed to expand without limit. A 55 minute lesson with a clear spine and twelve small concepts outperformed a 62 minute lesson where one topic ran unchecked. Adding time to the second session would not have fixed it. It would have produced 75 minutes of the same problem.

If a session consistently feels like it is not landing, the useful question is not "should we make it longer." It is "what took up the time, and was that the thing we came for."

Frequently Asked Questions

How long should a coding lesson for a child be? Around an hour works well for teenagers in my experience, but the length matters far less than the structure. In July my 55 minute session taught more than my 62 minute one with the same student, because the longer one let a single sub-topic consume most of the time.

Would a longer lesson help my child make faster progress? Usually not on its own. If a lesson is not landing, adding time typically extends the problem rather than solving it. Look at how many separate new ideas are being introduced and whether one of them is running away with the session.

Is it a bad sign if my child says "I don't know" a lot in a lesson? It depends where. During the main topic it is normal and useful. During a warm up or a review it usually means the warm up is too hard and should be cut short, which is a tutor problem rather than a student one.

Should a tutor admit when something is difficult? I think so, and it produced the best sequence I taught all month. Telling my student that I find a particular problem hard gave him permission to struggle with it instead of reading slow progress as failure. He solved it and could explain it back.

How can I tell whether a lesson went well if I was not in the room? Ask what the lesson was about and then ask them to explain one small piece of it. A student who can name the topic but cannot explain any of it often sat through a session where something else took up the time.

Related Articles

• What 30 Sessions of 1-on-1 Coding Actually Look Like for a Kid, how sessions accumulate into real progress.
• Python For Loops for Kids: 12 Examples, the topic this lesson was trying to introduce.
• Is 1-on-1 Coding Tutoring Worth It?, what close attention buys that a fixed course cannot.

The Bottom Line

Two sessions with the same student a week apart produced opposite results, and the longer one taught less. The cause was a five minute warm up that ran seventeen minutes and became harder than the lesson it was introducing. Session length is not the lever. Concept density and the discipline to cut a failing warm up are. I would rather run 55 focused minutes than 75 unfocused ones, and I now cap the warm up before the lesson starts.

Want to see what a well structured session actually covers? Book a free Discovery Call and I will walk you through a real lesson plan for your child's level.