Free Teacher Tools for Computer Science
Four free, interactive tools that make algorithms, logic gates and data structures visible. No sign-up, no downloads. Open one and start teaching.
Interactive Ciencias de la Computación tools
Each tool runs in the browser and shows every step, so students can see how computers sort, decide, store and search. Project them for the whole class, or let students explore on their own.
Sorting Visualizer
Watch Bubble Sort, Selection Sort, Insertion Sort, Merge Sort and Quick Sort put a list in order, one step at a time. Students pause, rewind and count every comparison and swap.
- Live variables (i, j, pivot) shown under the bars
- A plain-English plan in Easy, Python code in Advanced
- Compare algorithms on random, reversed or nearly sorted data
Logic Gate Simulator
Drag AND, OR, NOT and XOR gates onto the board, wire them to switches and lamps, and watch the truth table fill in as students build. Load a half adder, full adder or multiplexer to explore.
- Truth table and Boolean expression update live
- Challenges such as “build OR from NAND gates” and “majority vote”
- All 7 gates and Boolean algebra notation in Advanced
Data Structure Playground
Push and pop a stack, enqueue and dequeue a queue, follow pointers through a linked list, and insert, search and delete in a binary search tree, with animations at every step.
- Step counter that makes Big-O easy to see
- In-order, pre-order and post-order traversals
- Python code for every operation in Advanced
Search Race
Pick a target number and race linear search against binary search on the same list. Students predict the winner, then see why halving the list beats checking every item.
- Comparison counters and a race log for class discussion
- An experiment that charts lists from 10 to 1,000 items
- Live low, mid and high values in Advanced
One tool, two levels
Every tool has an Easy and an Advanced switch, so the same activity works for a student seeing an algorithm for the first time and for one preparing for AP Computer Science Principles.
Easy Principiantes
- Plain-English steps that light up as the tool runs
- Friendly names such as “smallest so far” instead of variables
- Speed shown in words and banana ratings, not Big-O
- Fewer options, so beginners can focus on the big idea
Advanced Going deeper
- Real Python code with the running line highlighted
- Live variables such as
min_idx = 4ymid = 17 - Big-O tables with clear explanations of O(n), O(n²) and O(log n)
- Extra operations, gates and harder challenges
?level=advanced o ?level=easy to the end of any tool’s address. Each tool also remembers the level a student picked.How teachers use these free tools
No setup and no accounts means you can fit them into almost any lesson.
Whole-class demo
Project a tool, step through slowly and ask the class to call out the next move before you click.
Predict, then test
Students write down a prediction, such as which search will win, then run the tool to check and explain the result.
Stations and pairs
Set up one tool per station. Pairs complete the “Try this in class” prompt on each tool and report back.
Review and homework
Share a link for homework or test review. The tools run on any school device, with nothing to install.
Activity ideas for each level
Suggested starting points for each tool, at both levels.
| Tool | Key concepts | Easy level | Advanced level |
|---|---|---|---|
| Sorting Visualizer | Algorithms, comparisons, efficiency | Follow Bubble Sort step by step and count the swaps | Compare O(n²) and O(n log n) sorts on the same data |
| Logic Gate Simulator | Boolean logic, truth tables, binary addition | Build a smart alarm with AND and OR gates | Build a full adder, or any gate from NAND alone |
| Data Structure Playground | Stacks, queues, linked lists, trees | Explore last in, first out vs first in, first out | Trace BST insert and delete, and see why balance matters |
| Search Race | Linear and binary search | Predict the winner and explain why halving is faster | Connect the results to O(n) vs O(log n) growth |
Made by the CodeMonkey team
CodeMonkey has helped millions of students learn to code through game-based courses in block coding, CoffeeScript and Python. We built these free teacher tools to make the hardest computer science ideas easy to see.
Frequently asked questions
Are these teacher tools really free?
Yes. All four interactive computer science tools are completely free for teachers, students and parents, with no trial period and no paywall.
Do students need an account to use them?
No. There is nothing to sign up for or install. Students open the link and start exploring right away.
What is the difference between Easy and Advanced?
Easy mode explains every step in plain English, with friendly names and simple speed ratings. Advanced mode adds real Python code, live variables and Big-O, and covers AP Computer Science Principles topics such as binary search and Boolean logic.
Do the tools work on Chromebooks and iPads?
Yes. They run in any modern web browser on Chromebooks, Windows and Mac computers, iPads and other tablets. A laptop or tablet screen works best for the Logic Gate Simulator.
Do students need to know how to code?
No. Easy mode uses plain English. Advanced mode shows real Python code next to each step, which helps students connect what they see to the code they write.
Can I use the tools with my whole class at once?
Yes. Project a tool on the board for a class demo, or share the link so every student can work on their own device at the same time.