Tools

Interactive widgets that accompany articles on scienceabc.com.

• Molecular Geometry Predictor

  Set the number of bonding groups and lone pairs around a central atom. VSEPR rules predict the 3D shape (linear, bent, trigonal planar, tetrahedral, trigonal bipyramidal, seesaw, T-shaped, octahedral, square pyramidal, square planar), the bond angle, the AX_nE_m notation, and polarity — then click a real molecule to skin the template with its actual atoms.

• Gas Laws Explorer

  Drag pressure, volume, temperature, and mole sliders on a sealed cylinder with a sliding piston and a heater. Watch the piston rise and fall, particles speed up under heat, and PV = nRT come to life through Boyle’s, Charles’s, Gay-Lussac’s, Avogadro’s, and ideal-gas modes.

• Number Line Operations

  Step through integer addition, subtraction, and multiplication as jumps on a number line — including the “subtract = add the opposite” rewrite and the direction-flip for negative factors. Plus absolute value as distance from zero and inequalities as shaded rays with open or closed endpoints.

• Predator-Prey Population Simulator

  Tune the four Lotka-Volterra parameters and watch prey and predator populations oscillate — as a time graph, a phase plot orbiting around equilibrium, or as wandering dots being chased on a 2D grid.

• Vector Addition Sandbox

  Drag arrow tips on a 2D grid to add up to four vectors. Switch between head-to-tail chaining and x/y component decomposition, with magnitude, angle, and the resultant updating live in both views.

• Riemann Sum & Integration as Area

  Slice the area under a curve into rectangles and watch the sum approach the true integral. Switch between left, right, midpoint, and trapezoid rules across five functions, including one that dips below zero so you can see signed area cancel.

• Doppler Effect Animator

  Move a sound source past a stationary observer. Watch wavefronts compress in front and stretch behind, hear the sawtooth siren shift pitch as it passes, and push past Mach 1 to see the Mach cone form and trigger a sonic boom.

• Photosynthesis Interactive Diagram

  A clickable chloroplast cross-section. Tap the thylakoid to step through the light reactions (water split, ATP & NADPH made, O₂ out) or the stroma to walk the Calvin cycle. Inputs and outputs are tagged at every step.

• Acid-Base Titration Simulator

  Drip a base into an acid (or vice versa) and watch the pH curve, flask color, and indicator change in real time. Covers strong, weak, and polyprotic systems (acetic, ammonia, oxalic, phosphoric) with a slider mode and a drop-by-drop lab mode.

• Newton's Laws Sandbox

  Push a block with adjustable mass, applied force, and friction. Watch position, velocity, and acceleration graphs build in real time, with presets that demonstrate inertia, F = ma, and the static-friction barrier.

• Linear & Quadratic Function Explorer

  Drag sliders to reshape y = mx + b or y = ax² + bx + c. Slope, intercepts, vertex, axis of symmetry, discriminant, and roots update live, with standard, vertex, and factored forms of the parabola.

• Punnett Square Generator

  Predict offspring genotypes and phenotypes for any cross. Monohybrid or dihybrid, with complete, incomplete, and codominant dominance modes — plus real biology presets (Mendel's peas, snapdragons, ABO blood type).

• How the Atomic Model Evolved

  Step from Democritus to Dalton, Thomson, Rutherford, Bohr, and Schrödinger. Each entry shows the model's claim, the experiment that built it, and the finding that eventually broke it, with an SVG visualization of every model.

• Hardest Materials Compared

  Sortable list of 21 materials by Mohs and Vickers hardness — from talc to diamond — with the predicted-but-unmeasured candidates (lonsdaleite, wurtzite BN) flagged honestly. Compare any two side by side.

• Periodic Table: Why It's Arranged That Way

  Recolor the periodic table by block (s/p/d/f), period, group, atomic radius, ionization energy, or electronegativity. Click any element to see its electron configuration with the last-filled orbital highlighted and an explanation of why it sits in that exact row and column.

• How 1 + 2 + 3 + … = −1/12

  Slide N up to 200 and watch the partial sums of 1+2+3+… race off to infinity (so the answer is not −1/12 by ordinary summation). Then walk through the Euler/Ramanujan heuristic step by step and see how the Riemann zeta function makes −1/12 the unique consistent value.

• Sunrise & Sunset Around the World

  Pick any city and any date and see the sunrise time, sunset time, and day length, computed with the NOAA solar algorithm. Compare day length across latitudes for the same date, or watch one city's day-length curve through the year.

• Lactose Intolerance by Population

  Look up the share of adults who can't fully digest lactose, by world region or specific ethnic group — from East Asians (~95%) and Native Americans (~100%) to Scandinavians (~4%) and Maasai pastoralists (~20%). Every figure cites the primary peer-reviewed study it comes from.

• 360° Circle Explorer

  Pick any angle from 0° to 360° and see it instantly as degrees, a fraction of a turn, radians, DMS, and sin·cos. Drag the slider, type a value, enter a fraction, or click a preset.

• Planet Rotation Explorer

  Tap any planet (Mercury through Neptune) to see which way it spins, its axial tilt, and the length of its day. The two retrograde oddballs — Venus and Uranus — are flagged, and a sortable reference table puts all eight side by side.

• Throat Anatomy Explorer

  Tap any labeled part of the throat — pharynx, epiglottis, trachea, esophagus — to learn what it does. Switch between breathing and swallowing modes to see how the epiglottis flips to keep food out of your airway.

• Cell Division Explorer

  Step through every phase of mitosis, meiosis I, and meiosis II with animated chromosome diagrams. A side-by-side comparator highlights the differences, and a reverse "find a phase" lookup answers questions like "when do sister chromatids separate?"

• First Life on Earth Timeline

  Scrub from Earth's molten birth 4.54 billion years ago to today through ten life-on-Earth milestones — first oceans, LUCA, the oldest fossils, the Great Oxidation, eukaryotes, the Boring Billion, and the Cambrian explosion.

• pH Scale Explorer

  Drag a marker along a pH scale that extends from −3 to 17, with real substances pinned at their actual values — including the superacids and superbases that live outside the conventional 0–14 range. Compare any two substances and see how many times more acidic one is than the other.

• Post-mortem Timeline

  Scrub the slider through the first 72 hours after death to see when pallor, algor, livor, and rigor mortis appear, peak, and fade. A separate comparison view puts the four mortises side by side.

• Electron Shell Explorer

  Click any element on the periodic table and watch its electrons fill the K, L, M shells. See the valence shell highlighted, the octet status, and switch between Bohr diagram, shell notation (2, 8, 8, 18), and full Aufbau orbital configuration.

• Soil Horizon Explorer

  Tap any layer of a soil profile to see its depth, color, composition, and biology — then switch between forest, grassland, desert, tundra, and tropical biomes to see how soils change with climate.

• The Sun's Life Timeline

  Drag a scrubber through 4.6 billion years of past and ~7.7 billion years of future to see what the Sun looked like, looks like, and will look like — and what happens to Earth at every step.

• Dinosaur Size Comparator

  Pick any two or three theropods (and Argentinosaurus for scale shock) and see their silhouettes side by side at true real-world scale, with a human for reference.

• Reactivity Explorer

  An interactive periodic table heat-mapped by reactivity. Compare any two elements, see the metal and nonmetal trends, and find the top 10 most reactive elements.

• Electric Shock Calculator

  Pick a voltage (from AA battery to lightning) and see what current it would drive through your body — then look up what each milliamp range actually does.

• USB Connector Identifier

  Visual gallery of every USB connector type, with a transfer-speed calculator and a charger compatibility checker.

• Famous People IQ Lookup

  Searchable database of documented and estimated IQ scores, with side-by-side comparison.