51 free learning sites and tools, sorted by subject

AI and computing

Quick, Draw!

What it is: Draw a doodle and watch a neural network guess what it is.

Why it's worth it: You see how a model learns from millions of drawings. Open Quick, Draw! (opens in a new tab)

Teachable Machine

What it is: Train a simple model on your own photos, sounds or poses.

Why it's worth it: It turns "training data" from a buzzword into something you build. Open Teachable Machine (opens in a new tab)

TensorFlow Playground

What it is: Tinker with a small neural network right in the browser.

Why it's worth it: Change one setting and watch the pattern it learns change. Open TensorFlow Playground (opens in a new tab)

Which Face Is Real

What it is: Pick the real photo from a pair where one face was made by AI.

Why it's worth it: A quick, memorable lesson in spotting fakes. Open Which Face Is Real (opens in a new tab)

Survival of the Best Fit

What it is: A short game about how a hiring algorithm picks up human bias.

Why it's worth it: It shows why AI choices are only as fair as their data. Open Survival of the Best Fit (opens in a new tab)

CS50x from Harvard

What it is: Harvard's intro to computer science, free online.

Why it's worth it: A real, complete course with problem sets and lectures. Open CS50x from Harvard (opens in a new tab)

Raspberry Pi Projects

What it is: Step-by-step coding and making projects in Scratch, Python and more.

Why it's worth it: Hundreds of guided projects, from first steps to hardware. Open Raspberry Pi Projects (opens in a new tab)

MIT OpenCourseWare

What it is: Notes, problem sets and many video lectures from MIT courses.

Why it's worth it: Real college material on almost any subject, open to anyone. Open MIT OpenCourseWare (opens in a new tab)

Math and statistics

Desmos Graphing Calculator

What it is: A free online graphing calculator.

Why it's worth it: Type an equation and see the graph move as you change it. Open Desmos Graphing Calculator (opens in a new tab)

GeoGebra

What it is: Free calculators and apps for geometry, algebra and graphing.

Why it's worth it: Drag shapes and points to see math rules hold. Open GeoGebra (opens in a new tab)

Guess the Correlation

What it is: Look at a scatter plot and guess how strong the link is.

Why it's worth it: Builds a gut feel for data before any formula. Open Guess the Correlation (opens in a new tab)

Spurious Correlations

What it is: Funny charts of things that line up by pure chance.

Why it's worth it: The easiest way to remember that correlation is not cause. Open Spurious Correlations (opens in a new tab)

Monty Hall simulator

What it is: Play the famous three-door puzzle, then simulate it hundreds of times.

Why it's worth it: The numbers settle an argument your gut will lose. Open Monty Hall simulator (opens in a new tab)

Calculus Made Easy

What it is: Silvanus Thompson's friendly 1910 calculus book, free as an eBook.

Why it's worth it: A classic that explains calculus in plain words. Open Calculus Made Easy (opens in a new tab)

CK-12

What it is: Free digital textbooks, practice and simulations from a nonprofit.

Why it's worth it: Math and science readings with practice built in. Open CK-12 (opens in a new tab)

Khan Academy

What it is: Free courses with video lessons and practice.

Why it's worth it: A full path through math and much more, at no cost. Open Khan Academy (opens in a new tab)

Science and engineering

CraftingTable circuit simulator

What it is: Wire, code and run an emulated chip in the browser, no hardware needed.

Why it's worth it: Try electronics before buying a single part. Open CraftingTable circuit simulator (opens in a new tab)

Smithsonian 3D

What it is: Explore thousands of 3D scans of Smithsonian objects.

Why it's worth it: Spin a fossil or a spacesuit up close from home. Open Smithsonian 3D (opens in a new tab)

Bird Migration Explorer

What it is: An interactive map of the yearly journeys of hundreds of bird species.

Why it's worth it: Follow a bird from your backyard across continents. Open Bird Migration Explorer (opens in a new tab)

River Bend Lab

What it is: A browser simulation of a winding river; change the flow and watch it reshape.

Why it's worth it: Shows erosion happening in minutes instead of centuries. Open River Bend Lab (opens in a new tab)

Zygote Body

What it is: A 3D human anatomy atlas with a free version.

Why it's worth it: Peel back layers of the body one system at a time. Open Zygote Body (opens in a new tab)

Squishy Circuits dough recipes

What it is: Recipes for play dough that conducts electricity and dough that does not.

Why it's worth it: Light an LED with dough from your kitchen. Open Squishy Circuits dough recipes (opens in a new tab)

Pepper's ghost hologram

What it is: Build a floating "hologram" with clear plastic and a phone.

Why it's worth it: A cheap optics trick that teaches reflection. Open Pepper's ghost hologram (opens in a new tab)

Tea time chemistry

What it is: Butterfly pea tea changes color with acid, explained step by step.

Why it's worth it: Kitchen chemistry with a big color payoff. Open Tea time chemistry (opens in a new tab)

PhET Build an Atom

What it is: A free PhET simulation. Add protons, neutrons and electrons and watch the element, charge and mass change.

Why it's worth it: A built-in game then checks what your kid figured out. Open PhET Build an Atom (opens in a new tab)

Ages: Middle school, high school and university, per PhET.

HHMI BioInteractive Lizard Evolution Virtual Lab

What it is: A free virtual lab from HHMI on how anole lizards evolved on Caribbean islands.

Why it's worth it: Kids collect and graph data the way field biologists do. It runs right in the browser. Open HHMI BioInteractive Lizard Evolution Virtual Lab (opens in a new tab)

Ages: High school and college, per BioInteractive.

Science Buddies Racing Bristlebots

What it is: Build two tiny toothbrush robots and race them to see which bristles are faster.

Why it's worth it: A first circuit and a fair test in one day. The steps are free; Science Buddies puts parts at $20 to $50 and sells a kit through a partner. An adult cuts the toothbrush. Open Science Buddies Racing Bristlebots (opens in a new tab)

Ages: Kindergarten to grade 2, per Science Buddies.

My NASA Data Earth System Data Explorer

What it is: Make maps and graphs from more than 60 NASA satellite datasets in the browser.

Why it's worth it: Kids can look up real NASA data for where they live. Nothing to install. Open My NASA Data Earth System Data Explorer (opens in a new tab)

Ages: My NASA Data doesn't list one on this page.

NOAA Tornado in a bottle

What it is: Swirl water from one bottle into another to make a vortex, with a short NOAA video.

Why it's worth it: Two bottles, water and a tornado tube connector show how air moves through a tornado. Open NOAA Tornado in a bottle (opens in a new tab)

Ages: Grades K to 12, per NOAA.

Exploratorium Condiment Diver

What it is: A condiment packet in a water bottle sinks, floats or hovers when you squeeze the bottle.

Why it's worth it: Pressure and buoyancy with something from the fridge door. Open Exploratorium Condiment Diver (opens in a new tab)

Ages: Grades K to 12, per the Exploratorium.

Concord Consortium Geniventure

What it is: A free genetics game where kids breed virtual dragons.

Why it's worth it: Alleles, meiosis and inheritance turn into puzzles to solve. Open Concord Consortium Geniventure (opens in a new tab)

Ages: Middle school and high school, per the Concord Consortium.

Zooniverse Planet Hunters TESS

What it is: Look at star brightness data from NASA's TESS telescope and mark dips that could be planets.

Why it's worth it: It's a live research project, and no account is needed to take part. Open Zooniverse Planet Hunters TESS (opens in a new tab)

Ages: No age limit, per Zooniverse. Kids under 16 need a parent's OK to make an account.

SAPS Growing rapid-cycling Brassicas

What it is: A free guide from Science and Plants for Schools (UK) to growing fast plants in film pots.

Why it's worth it: Kids watch a whole plant life cycle indoors in a short time. You need rapid-cycling Brassica seeds. Open SAPS Growing rapid-cycling Brassicas (opens in a new tab)

Ages: Primary school age, per SAPS.

Data Nuggets: Hold on for your life, Part I

What it is: Real data on anole lizards measured just before Hurricane Irma, and the survivors after it.

Why it's worth it: Kids graph the data and decide if bigger toe pads helped lizards hold on. Open Data Nuggets: Hold on for your life, Part I (opens in a new tab)

Ages: K to 16 classrooms, per Data Nuggets. This one is Level 3.

Reading and writing

Project Gutenberg

What it is: Tens of thousands of free classic eBooks.

Why it's worth it: Most of the classics on any reading list, at no cost. Open Project Gutenberg (opens in a new tab)

CommonLit

What it is: A free reading library with texts, questions and lessons.

Why it's worth it: Good short reads with questions ready to go. Open CommonLit (opens in a new tab)

Semantle

What it is: A daily word game scored by how close your guess is in meaning.

Why it's worth it: Stretches vocabulary in a way spelling games do not. Open Semantle (opens in a new tab)

Growing Reader

What it is: A free tracker that records a read-aloud and counts words per minute.

Why it's worth it: See reading fluency improve week by week. Open Growing Reader (opens in a new tab)

Anki

What it is: Flashcards that space out your reviews; desktop and Android are free.

Why it's worth it: Remember more with less study time. Open Anki (opens in a new tab)

Google Scholar

What it is: Search real research papers and books.

Why it's worth it: Teaches how to find a real source instead of a guess. Open Google Scholar (opens in a new tab)

History and geography

Ken Burns in the Classroom

What it is: Free documentary clips with lesson plans from PBS LearningMedia.

Why it's worth it: Strong film clips with questions ready for discussion. Open Ken Burns in the Classroom (opens in a new tab)

Retro Report Education

What it is: Short free documentaries with lessons on history, civics and science.

Why it's worth it: Connects past events to today's news. Open Retro Report Education (opens in a new tab)

GeoLibre

What it is: A free, open-source map app that runs in the browser.

Why it's worth it: Real map-making tools without installing anything. Open GeoLibre (opens in a new tab)

Al-Idrisi's 1154 world map

What it is: A Library of Congress look at a world map drawn with south at the top.

Why it's worth it: Flips how you see a map, literally. Open Al-Idrisi's 1154 world map (opens in a new tab)

Gapminder Worldview Upgrader

What it is: Quick quizzes that test and fix common wrong ideas about the world.

Why it's worth it: Facts about the world that most adults get wrong. Open Gapminder Worldview Upgrader (opens in a new tab)

Art and music

Practice Drawing This

What it is: A free 3D drawing reference you can turn to any angle.

Why it's worth it: Draw from a model you can spin, not a flat photo. Open Practice Drawing This (opens in a new tab)

Angle Ref

What it is: A drawing reference site. Turn a 3D skull to the angle you want, and it finds real photos of heads, poses, hands or animals at that angle.

Why it's worth it: Free daily searches, and every photo is openly licensed and credited. Open Angle Ref (opens in a new tab)

Chrome Music Lab

What it is: Browser music experiments for rhythm, melody and sound.

Why it's worth it: Make a song in minutes with no music lessons. Open Chrome Music Lab (opens in a new tab)

Tate Kids

What it is: Art games, quizzes and make-at-home ideas from the Tate museum.

Why it's worth it: A real museum's playful side. Open Tate Kids (opens in a new tab)

Paint 'n' Play

What it is: A digital painting tool from the National Gallery of Art.

Why it's worth it: Paint with brushes inspired by works in the collection. Open Paint 'n' Play (opens in a new tab)

BandLab for Education

What it is: A browser music studio with instruments and recording.

Why it's worth it: Record and mix a track with no software to buy. Open BandLab for Education (opens in a new tab)