Science Simulations
PhET, Algodoo, Labster, CK-12 — virtual labs and physics / chemistry / biology sims.
Hands-on science lab is irreplaceable, but virtual sims close 70-80% of the gap and cost nothing. Pair these with math tools, a LMS, and content discovery to scaffold full units.
The dominant free pick
- ★ ★ PhET Interactive Simulations (CU Boulder) — free + CC-BY; ~150 physics, chemistry, biology, earth-science, math sims. HTML5; runs on Chromebook / iPad / Android. Translated to 100+ languages. The single most-used free science resource on Earth.
General-purpose physics
- Algodoo — free; 2D rigid-body physics sandbox; great for K-8 mechanics.
- Newton's Lab / xCos / Scilab Xcos — open-source dynamics simulation.
- Working Model 2D — paid; engineering-grade.
- MATLAB / Simulink — paid; see STEM tools.
- GeoGebra — physics applets; see STEM tools.
Chemistry
- ★ MolView — free; web 3D molecule viewer.
- Avogadro — GPL; molecular editor.
- Jmol / JSmol — LGPL; classic web molecule viewer.
- ChemSketch (ACD/Labs) — free for academia.
- PhET Chemistry sims, CK-12 Chemistry FlexBook.
Biology
- BioInteractive (HHMI) — free; HHMI's high-school biology resources, simulations, video.
- Cell Collective — free for educators; build dynamic biological models.
- Foldit — free; protein-folding game; the famous "citizen-scientist" platform.
- iNaturalist + Seek — free; citizen-science species identification; great for field work.
- NetLogo — GPL; agent-based modelling; ecology / population dynamics.
Earth / space / climate
- Stellarium — GPL; planetarium for desktop and web. See planetariums.
- Climate Time Machine (NASA) — free; visualisations of climate data.
- Google Earth Pro — free; with Google Earth Studio for animated tours.
- EduMedia — paid; subscription science animation library; popular in EU schools.
Virtual labs (paid, professional)
- Labster — paid VR / browser virtual lab; medicine, biology, chemistry; widely adopted in universities.
- Smart Science — paid; high school virtual lab.
- Beyond Labz — paid; chemistry / physics virtual labs.
- HHMI BioInteractive virtual labs — free.
Curricula / textbook-aligned
- CK-12 Foundation — free; FlexBooks (textbooks), simulations, adaptive practice; aligned to US standards.
- OpenStax — free; open-licence university textbooks; see OER.
- Concord Consortium — free; STEM tools (CODAP for data, SAGE2, WISE projects).
- MIT BLOSSOMS — free video lessons + activities; high school STEM.
Pick this if…
- Default free K-12 science sims: PhET.
- Mechanics sandbox K-8: Algodoo.
- Chemistry molecule viewer: MolView or Jmol.
- Biology agent-based modelling: NetLogo.
- Field biology / species ID: iNaturalist + Seek.
- University-grade virtual lab, paid: Labster.
- Free aligned curriculum + sims: CK-12.