List of Beginning Python MicroSims

Interactive Micro Simulations to help students beginning Python programming. Click any card to open the MicroSim.

• Code Stepper

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  Step through a short Python program one line at a time and watch the output appear — see top-to-bottom execution with your own eyes. (Chapters 1-2)

• Variable Memory Model

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  Watch labeled memory boxes get created, read, and replaced as a script runs — the sticky-note metaphor made real. (Chapter 3)

• Function Call Flow

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  Trace a function call in slow motion: the argument flies into the parameter slot and the return value flies back. (Chapter 4)

• Turtle State Inspector

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  Step through turtle commands while a dashboard reveals the turtle's hidden state: position, heading compass, and pen. (Chapter 5)

• Expression Evaluator

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  Watch 2 + 3 * 4 collapse one operation at a time in the exact order Python evaluates it — PEMDAS made visible. (Chapter 6)

• Modulo Clock

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  See the remainder as wrap-around counting on a dial and as leftover dots — the % operator made concrete. (Chapter 6)

• For-Loop Stepper

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  Crank a for loop by hand: watch i change, the arrow jump back to the top, and a turtle draw one square side per trip. (Chapter 7)

• Range Explorer

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  Slide start, stop, and step and watch the number line light up — the stop value is a hollow ring because it is never included. (Chapter 7)

• Control Flow Explorer

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  Move a score slider and watch exactly one path through an if/elif/else flowchart glow green — later checks are never even looked at. (Chapter 9)

• Boolean Logic Lab

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  Wire True/False inputs into and, or, and not — and catch Python skipping the second input when the first one decides. (Chapters 9, 19)

• While-Loop Stepper

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  Feel the check-run-check rhythm of a while loop — and safely watch an infinite loop spin inside its cage. (Chapter 10)

• Scope Inspector

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  Variables live in rooms: watch a Function room appear during a call, shadow the global, and vanish at return. (Chapter 11)

• RGB Color Mixer

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  Mix red, green, and blue, watch the hex code assemble itself, and copy the pencolor line straight into your turtle art. (Chapter 12)

• String Slicer

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  Drag start and end handles over letter tiles and watch word[2:7] build itself — the end is never included, and now you can see why. (Chapters 8, 14)

• List Index Explorer

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  Append, insert, and pop a list of colored boxes and watch every index renumber — plus the TypeError a string gives instead. (Chapters 15-16)

• Stack and Queue Simulator

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  Feed the same letters into a stack of plates and a waiting line — then watch them leave in opposite orders. (Chapters 16, 30)

• Dice Roll Histogram

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  Roll 1, 100, or 1000 dice and watch chaos flatten into a pattern — then find the mountain hiding in two-dice sums. (Chapter 17)

• Sine Wave Explorer

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  Drag amplitude, frequency, and phase sliders and watch y = A × sin(f·x + p) re-plot instantly. (Chapter 18)

• Unit Circle Degrees and Radians

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  Drag a point around the unit circle and read the angle in degrees, radians, and multiples of π — with sin and cos bars. (Chapter 18)

• Set Operations Venn

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  Type two sets, watch the chips land in the right regions, and light up union, intersection, and difference. (Chapter 20)

• Dictionary Key Lookup

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  Type a key and the right drawer springs open in one hop — or hit a KeyError — then race the dict against a list. (Chapter 21)

• Recursion Call Stack

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  Watch factorial(4) stack frames pile up to the gold base case, then unwind as each paused multiplication fills in. (Chapters 23-24)

• Fractal Tree Explorer

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  Sculpt a recursive tree with angle, depth, and shrink sliders — every recursion level wears its own color. (Chapter 24)

• Object Instance Inspector

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  A dashed blueprint, solid instance cards, and a glowing arrow that shows exactly which dog self is. (Chapter 25)

• Inheritance Explorer

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  Click a method call and watch the lookup climb the class tree — overrides shadow the parent, and super() climbs on purpose. (Chapter 25)

• JSON to Python Type Mapper

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  Edit JSON on the left and watch the Python objects appear on the right — true becomes True, null becomes None. (Chapter 27)

• Regex Match Lab

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  Type a pattern, watch matches light up live, and read the pattern as plain-English chips — regex stops being magic. (Chapter 29)

• Sorting Algorithm Comparer

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  Step three classic sorts one comparison at a time, then race bubble vs insertion on identical data — the winner depends on the data. (Chapter 30)

• Search Race

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  Linear search plods box by box while binary search throws away half the shelf per check — and a shuffled-shelf trap shows why sorted matters. (Chapter 30)

• Graph Traversal Explorer

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  Step BFS and DFS over the same graph with the live queue or stack beside it — then watch BFS reveal the shortest path. (Chapter 30)