Using trace tables
Lesson details
Learning outcome
I can use trace tables to trace how variables change in a while loop.
Key learning points
- Trace tables are used to record how the values of variables change during the execution of a program.
- Trace tables and while loops help debug programs.
Keywords
Trace table - a tool used to track the values of variables and the flow of execution in an algorithm or program, step by step
Condition - an expression that evaluates to True or False
Common misconception
The condition in a while loop is only checked once. The loop will always run a fixed number of times.
Remind students that the condition is checked before each iteration. The loop repeats only while the condition is True. Variable changes inside the loop affect whether it continues or stops.
Teacher tip
Model how the condition is re-evaluated with each loop cycle. Walk through a trace table together, updating the variable and condition step by step.
Equipment
Pupils will need access to a device that can edit and run Python programs. Examples in this lesson use the RPF Code Editor https://oak.link/python-editor
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What is iteration in programming?
Q2.What does a condition in programming evaluate to?
Q3.What is the keyword for condition-controlled iteration in Python?
Q4.When does a while loop stop executing?
Q5.What happens if the condition in a while loop is always True?
Q6.Arrange the steps of a while loop.
Assessment exit quiz
6 Questions
Q1.Match the term to its definition.
tracks variable values step by step
logical expression controlling program flow
repeats code while a condition is True
fixing errors in a program
Q2.What is the purpose of a trace table?
Q3.What happens if the condition in a while loop is False?
Q4.When is the condition in a while loop checked?
Q5.What does a trace table record?
Q6.Arrange these steps in the correct order for using a trace table.
To help you plan your 10 computer science lesson on: Using trace tables, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 computer science lesson on: Using trace tables, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
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The assessment exit quiz will test your pupils' understanding of the key learning points.
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Explore more key stage 4 computer science lessons from the Programming: iteration unit, dive into the full secondary computer science curriculum, or learn more about lesson planning.