Science calculator glossary: units, formulas & concepts

Air Density calculates density of air from temperature, pressure, and humidity, using the ideal gas law with a humidity correction.

Allele Frequency calculates allele frequencies from genotype counts or numbers of each allele in a population.

Alligation calculates mixing ratio of two solutions of different concentrations to achieve a target concentration, using the alligation method.

Angular Momentum calculates angular momentum from moment of inertia and angular velocity (L = Iω), or from mass, velocity, and radius for a point mass.

Angular Velocity calculates angular velocity from RPM, frequency, or linear speed and radius, and converts between rad/s, RPM, and degrees per second.

Animal Gestation estimates due date and gestation window for a pregnant animal — dog, cat, cow, horse, and more — from the breeding date.

Annealing Temperature calculates PCR annealing temperature from primer melting temperatures, using the lower Tm minus an offset or the primer-pair Ta formula.

Arrhenius Equation calculates reaction rate constant, activation energy, or temperature with the Arrhenius equation, including the two-temperature form.

Average Atomic Mass calculates average atomic mass of an element from its isotopes' masses and natural abundances, or find an unknown abundance.

Avogadro's Number converts moles and number of particles (atoms, molecules, ions) using Avogadro's number, and from mass via molar mass.

Banked Curve calculates ideal banking angle or safe speed for a curve from the radius, speed, and friction, for road and tracks design.

Beat Frequency calculates beat frequency from two nearby frequencies, or find the unknown frequency of a tone from a known reference and the beats heard.

Beer-Lambert Law calculates absorbance, concentration, molar absorptivity, or path length using the Beer-Lambert law (A = εlc), plus transmittance.

Bernoulli's Equation solves for Bernoulli's equation for pressure, velocity, or height at two points in a flowing fluid, conserving energy along a streamline.

Binding Energy calculates mass defect and nuclear binding energy of an isotope from its protons, neutrons, and atomic mass, in MeV and per nucleon.

Bohr Model calculates energy level, orbital radius, and electron velocity of a hydrogen-like atom in the Bohr model, and the transition energy between levels.

Boiling Point Elevation calculates boiling point elevation of a solution from molality, the van't Hoff factor, and the ebullioscopic constant.

Bond Order calculates bond order of a diatomic molecule from the number of bonding and antibonding electrons (molecular orbital theory), with stability.

Boyle's Law solves for Boyle's law (P₁V₁ = P₂V₂) for the pressure or volume of a gas at constant temperature.

Bragg's Law calculates diffraction angle, wavelength, or interplanar spacing for X-ray diffraction using Bragg's law (nλ = 2d·sinθ).

Brewster's Angle calculates Brewster's angle (the polarization angle) from the refractive indices of two media (θB = arctan(n2/n1)).

Brinell Hardness calculates Brinell hardness number (BHN) from the applied load, indenter diameter, and indentation diameter, with an approximate tensile-strength estimate.

Buffer Capacity calculates buffer capacity of a solution from the buffer concentration, pKa, and pH, showing how much acid or base it can absorb.

Bulk Modulus calculates bulk modulus of a material from the pressure change and the fractional volume change (K = -deltaP/(deltaV/V)).

Buoyancy calculates buoyant force from Archimedes' principle using fluid density and displaced volume, and check whether an object floats or sinks.

Capacitive Reactance calculates capacitive reactance from frequency and capacitance (Xc = 1/(2πfC)), and the inductive reactance for comparison.

Capacitor calculates capacitance, charge, voltage, and stored energy for a capacitor, plus series and parallel capacitor combinations.

Carnot Efficiency calculates maximum (Carnot) efficiency of a heat engine from its hot and cold reservoir temperatures, and the work output from heat input.

Carrying Capacity estimates carrying capacity of an environment from available resources and per-individual consumption, and the logistic growth rate near capacity.

Cell Density calculates cell concentration from a hemocytometer count, total cells, and the volume or dilution needed to reach a target density.

Centrifugal Force calculates (apparent) centrifugal force on an object in circular motion from mass, speed or angular velocity, and radius.

Centripetal Force calculates centripetal force and acceleration for circular motion from mass, speed, and radius, and solve for any variable.

Charles's Law solves for Charles's law (V₁/T₁ = V₂/T₂) for the volume or temperature of a gas at constant pressure, with Kelvin handled.

Balance any chemical equation automatically, finding the smallest whole-number coefficients, with the balanced equation and element counts.

Use the Clausius-Clapeyron equation to find a vapor pressure, temperature, or enthalpy of vaporization from two-point data.

Coefficient of Performance calculates coefficient of performance (COP) of a heat pump, refrigerator, or air conditioner from heat moved and work input, plus the Carnot COP limit.

Combined Gas Law solves for the combined gas law (P₁V₁/T₁ = P₂V₂/T₂) for any pressure, volume, or temperature of a fixed amount of gas.

Compton Scattering calculates Compton wavelength shift of a photon scattered by an electron from the scattering angle (Δλ = (h/mₑc)(1 − cosθ)).

Coulomb's Law calculates electrostatic force between two charges using Coulomb's law, and solve for charge or distance.

Darcy-Weisbach calculates head loss due to friction in a pipe using the Darcy-Weisbach equation from the friction factor, length, diameter, and velocity.

De Broglie Wavelength calculates de Broglie wavelength of a particle from its mass and velocity (or momentum), λ = h/p, with the matter-wave interpretation.

Degree of Unsaturation calculates degree of unsaturation (index of hydrogen deficiency) of a molecule from its molecular formula, indicating rings and double bonds.

Density is a physical substance's mass per unit volume (ρ = m/V), quantifying how closely matter is packed within a defined space.

Density Altitude calculates density altitude from pressure altitude and temperature, for aviation performance and engine tuning.

Dew Point calculates dew point from air temperature and relative humidity using the Magnus formula, with a comfort interpretation.

Diffraction Grating calculates diffraction angle, wavelength, or grating spacing using the grating equation (d sin theta = m lambda), from lines per mm and the order.

Dihybrid Cross generates a 4×4 dihybrid Punnett square from two parent genotypes and calculates the 9:3:3:1 genotype and phenotype ratios.

Dilution Factor calculates dilution factor, final concentration, or required volumes for a single dilution using C1V1 = C2V2.

DNA Concentration calculates DNA or RNA concentration from a spectrophotometer A260 reading, with the dilution factor and the 260/280 purity ratio.

DNA Copy Number calculates number of DNA molecules (copy number) from the mass and length of a DNA fragment, for qPCR standards and cloning.

DNA Molecular Weight estimates molecular weight of a DNA or RNA sequence from its length and strandedness, and converts between mass, moles, and copy number.

Transcribe a DNA sequence into mRNA and translate it into an amino acid sequence, with the complementary and reverse-complement strands.

Doppler Effect calculates observed frequency of a sound source moving toward or away from an observer using the Doppler effect, for any source and observer speeds.

Doubling Time calculates cell population doubling time and number of generations from initial and final counts over an elapsed time.

Drag Force calculates aerodynamic drag force from air density, velocity, drag coefficient, and reference area, and solve for any variable.

E=mc² calculates energy equivalent of a mass (E = mc²), or the mass equivalent of an energy, in joules, kWh, and megatons of TNT.

Efficiency calculates energy or power efficiency as useful output over total input, and the energy lost, for machines and engines.

Elastic Collision calculates final velocities of two objects after a 1D elastic collision from their masses and initial velocities, conserving momentum and energy.

Electric Field calculates electric field from a point charge or from force per charge, and the force on a charge in a field.

Electric Power calculates electrical power, current, voltage, or resistance using P = VI, P = I²R, and P = V²/R, and estimates energy use and cost.

Electrolysis calculates mass of substance deposited or the time and current needed in electrolysis using Faraday's laws.

Electron Configuration determines electron configuration of an element or ion by atomic number, with the noble-gas shorthand, orbital diagram, and valence electrons.

Electronegativity calculates electronegativity difference between two elements (Pauling scale) and classify the bond as nonpolar, polar covalent, or ionic.

Elongation calculates elongation of a material under load (ΔL = FL/AE) from force, length, area, and Young's modulus, plus percent elongation.

Empirical Formula determines empirical formula from percent composition or masses, then the molecular formula from the molar mass.

Energy & Work calculates kinetic and potential energy, work, and power with built-in unit conversion.

Enthalpy calculates enthalpy change of a reaction from bond energies (bonds broken minus bonds formed), or from q = mcΔT for a calorimetry experiment.

Entropy calculates standard entropy change of a reaction from the entropies of products and reactants, or the entropy change from heat and temperature.

Equilibrium Constant calculates equilibrium constant Kc from equilibrium concentrations of reactants and products with their coefficients, and interpret the result.

Escape Velocity calculates escape velocity from a planet or star using its mass and radius, with presets for Earth, the Moon, and Mars.

Factor of Safety calculates factor of safety from the material strength and the working (applied) stress, or the allowable stress for a target safety factor.

Faraday's Law calculates induced EMF in a coil from the change in magnetic flux over time and the number of turns (Faraday's law of induction).

Force calculates force, mass, or acceleration using F=ma.

Free Fall calculates free fall time, velocity, and distance.

Freezing Point Depression calculates freezing point depression of a solution from molality, the van't Hoff factor, and the cryoscopic constant.

Friction calculates force of friction from the normal force and coefficient of friction, and solve for the coefficient or normal force.

Froude Number calculates Froude number from flow velocity and characteristic length, and classify open-channel flow as subcritical, critical, or supercritical.

Gay-Lussac's Law solves for Gay-Lussac's law (P₁/T₁ = P₂/T₂) for the pressure or temperature of a gas at constant volume.

GC Content calculates GC content of a DNA sequence (percent G + C), plus AT content and base composition, by pasting the sequence.

Gibbs Free Energy calculates Gibbs free energy (ΔG = ΔH − TΔS) to determine reaction spontaneity, with solutions for enthalpy, entropy, or temperature.

Graham's Law compares the effusion or diffusion rates of two gases using Graham's law, from their molar masses.

Gravitational Force calculates gravitational force between two masses using Newton's law of universal gravitation, and solve for mass or distance.

Half-Life solves for remaining amount, initial amount, elapsed time, or half-life using the exponential decay law, plus decay constant and mean lifetime.

Hardy-Weinberg calculates allele and genotype frequencies with the Hardy-Weinberg equations (p+q=1, p²+2pq+q²=1) from a known frequency or a genotype count.

Hazen-Williams calculates head loss or flow rate in a water pipe using the Hazen-Williams equation from the roughness coefficient, diameter, and length.

Heat Index calculates heat index (feels-like temperature) from air temperature and relative humidity using the NWS regression, with a risk category.

Heat Transfer calculates heat energy (Q=mcDT), conduction rate, cooling curves, and insulation R-values.

Heat Transfer Coefficient calculates convective heat transfer coefficient from the heat transfer rate, surface area, and temperature difference (Q = hAΔT).

Heisenberg Uncertainty calculates minimum uncertainty in position, momentum, energy, or time using the Heisenberg uncertainty principle (Δx·Δp ≥ ħ/2).

Henderson-Hasselbalch calculates pH of a buffer solution from pKa and the ratio of conjugate base to acid using the Henderson-Hasselbalch equation.

Hess's Law calculates overall enthalpy change of a reaction from step reactions using Hess's law, or from formation enthalpies.

Hohmann Transfer calculates two burns and total delta-v for a Hohmann transfer between two circular orbits, plus the transfer time.

Hooke's Law calculates spring force, spring constant, or displacement using Hooke's law (F = kx), plus the elastic potential energy stored.

Hoop Stress calculates hoop (circumferential) and longitudinal stress in a thin-walled pressure vessel or pipe from internal pressure, radius, and wall thickness.

Hydraulic Radius calculates hydraulic radius (flow area divided by wetted perimeter) for common channel shapes — rectangular, circular, and trapezoidal.

Hydrostatic Pressure calculates hydrostatic pressure at a depth in a fluid (P = ρgh), with or without atmospheric pressure, and solve for depth or density.

Ideal Gas Law solves for the ideal gas law (PV = nRT) for pressure, volume, moles, or temperature, with unit-aware inputs and the gas constant handled for you.

Impulse calculates impulse from force and time or from momentum change, and solve for the average force in an impact.

Inclined Plane calculates forces on an object on a ramp: gravity components, normal force, friction, net force, and acceleration down the incline.

Inductance calculates inductance of a solenoid from its turns, area, and length, the energy stored, and the EMF from a changing current.

Ionic Strength calculates ionic strength of a solution from the concentration and charge of each ion (I = ½Σcᵢzᵢ²).

Isoelectric Point calculates isoelectric point (pI) of an amino acid or peptide from its pKa values, the pH at which it carries no net charge.

Kinematics solves for SUVAT kinematics for velocity, acceleration, distance, or time, plus projectile motion.

Kinetic energy is the mechanical energy possessed by an object due to its motion, proportional to its mass and the square of its velocity (KE = ½mv²).

Ksp calculates solubility product (Ksp) from molar solubility, or molar solubility from Ksp, for salts of common stoichiometries.

Latent Heat calculates heat needed for a phase change (melting or boiling) using Q = mL, with solutions for mass or the latent heat constant.

Lattice Energy estimates lattice energy of an ionic compound using the Kapustinskii equation from ion charges, count, and radii.

LC Resonant Frequency calculates resonant frequency of an LC circuit from inductance and capacitance, with solutions for L or C to hit a target frequency.

Length Contraction calculates relativistic length contraction — how much shorter a moving object appears — from its proper length and velocity.

Lens Equation solves for the thin-lens and mirror equation (1/f = 1/do + 1/di) for focal length, object, or image distance, plus magnification and image type.

Lens Maker's Equation calculates focal length of a lens from its refractive index and the radii of curvature using the lens maker's equation, plus lens power in diopters.

Ligation calculates amount of insert DNA needed for a cloning ligation reaction from the vector amount and the desired insert:vector molar ratio.

Light Year converts light years, kilometers, miles, astronomical units, and parsecs, and finds the light-travel time for any distance.

Limiting Reagent determines limiting reactant from two reactant amounts and their coefficients, and finds the theoretical product yield and excess left over.

Log Reduction calculates log reduction and percent reduction of a microbial population from initial and final counts, for disinfection and sterilization.

Lorentz Force calculates Lorentz force on a moving charge in electric and magnetic fields (F = qE + qvB·sinθ), for either or both fields.

Luminosity calculates luminosity of a star from its radius and temperature (Stefan-Boltzmann), or from apparent brightness and distance, in solar luminosities.

Mach Number calculates Mach number from an object's speed and the local speed of sound (which varies with temperature), with the flow regime.

Magnetic Flux calculates magnetic flux through a surface from the field strength, area, and angle (Φ = B·A·cosθ), with solutions for any variable.

Magnification calculates magnification from image and object size or distances, and total magnification for a microscope or telescope from lens powers.

Malus's Law calculates transmitted intensity of polarized light through a polarizer using Malus's law (I = I₀·cos²θ), with solutions for angle.

Manometer calculates pressure difference measured by a manometer from the fluid density and the height difference of the liquid columns (ΔP = ρgh).

Mass Percent calculates mass percent of an element in a compound or a solute in a solution (percent composition by mass).

Mean Free Path calculates mean free path of gas molecules from temperature, pressure, and molecular diameter, or from number density.

Mechanical Advantage calculates mechanical advantage of a lever, pulley, inclined plane, wheel-and-axle, or screw, plus the effort force needed.

Michaelis-Menten calculates enzyme reaction velocity with the Michaelis-Menten equation from Vmax, Km, and substrate concentration, with solutions for any variable.

Microscope Field of View calculates microscope field of view diameter at any magnification from the field number, and estimates the size of an object in view.

Mohr's Circle calculates principal stresses, maximum shear stress, and principal angle from a 2D stress state (σx, σy, τxy) using Mohr's circle.

Molality calculates molality (moles of solute per kilogram of solvent), and solve for moles or solvent mass.

Mole Fraction calculates mole fraction of each component in a mixture from moles or masses, and the mole percent.

Moles converts moles, mass, and molar mass, and finds the number of particles using Avogadro's number.

Moment of Inertia calculates moment of inertia of common shapes — point mass, rod, disk, sphere, hoop, and cylinder — about their standard axes.

Momentum is the product of an object's mass and its linear velocity (p = mv), quantifying its motion and physical resistance to stopping.

Mutation Frequency calculates mutation frequency and mutation rate from the number of mutants and the total population or number of generations.

Natural Frequency calculates natural frequency of a spring-mass system or a cantilever beam, and the angular frequency and period.

Nernst Equation calculates cell potential of an electrochemical cell under non-standard conditions with the Nernst equation.

Net Ionic Equation converts a balanced molecular equation into the complete and net ionic equations by dissociating strong electrolytes and removing spectator ions.

Newton's Law of Cooling calculates temperature of a cooling object over time using Newton's law of cooling, or the time to reach a target temperature.

Newton's Laws calculates force, mass, or acceleration using Newton's second law with friction and inclined plane support.

Normality calculates normality from molarity and equivalents, or from equivalents of solute and volume, and converts between normality and molarity.

Orbital Period calculates orbital period, orbital velocity, or altitude of a satellite using Kepler's third law and the central body's mass.

Orbital Velocity calculates orbital velocity needed to orbit a central body at a given radius, plus the escape velocity, from the body's mass.

Orifice Flow calculates flow rate through an orifice from the discharge coefficient, area, and pressure difference (Q = Cd·A·√(2ΔP/ρ)).

Osmotic Pressure calculates osmotic pressure of a solution from its molar concentration, temperature, and van't Hoff factor (Π = iMRT).

Oxidation Number determines oxidation number of an element in a compound or ion using the standard oxidation-state rules.

Parallax calculates distance to a star from its parallax angle (distance in parsecs = 1/parallax in arcseconds), in parsecs and light years.

Partial Pressure calculates partial pressure of a gas in a mixture using Dalton's law and mole fractions, and the total pressure.

Pendulum calculates period and frequency of a simple pendulum from its length and gravity, with solutions for length needed for a target period.

Percent Ionization calculates percent ionization of a weak acid or base from its Ka/Kb and concentration, with the equilibrium H+ and pH.

Percent Purity calculates percent purity of a sample from the mass of pure substance and total sample mass, or from a reaction yield.

Percent Yield calculates percent yield from actual and theoretical yield, with solutions for actual or theoretical yield.

PH calculates pH, pOH, and hydrogen or hydroxide ion concentration for acids and bases, and converts between them with the acid-base scale.

Photoelectric Effect calculates maximum kinetic energy of ejected electrons, the threshold frequency, or the work function in the photoelectric effect.

Photon Energy calculates energy of a photon from its wavelength or frequency (E = hf = hc/λ), in joules and electronvolts.

Pipe Velocity calculates flow velocity in a pipe from the volumetric flow rate and the pipe diameter (v = Q/A), with solutions for flow rate or diameter.

PKa converts Ka and pKa (and Kb/pKb), and finds the pH of a buffer from pKa and the acid-base ratio.

POH calculates pOH from hydroxide concentration or from pH, and converts between pH, pOH, and ion concentrations.

Poiseuille's Law calculates volumetric flow rate through a pipe using Poiseuille's law from the radius, pressure difference, viscosity, and length.

Poisson's Ratio calculates Poisson's ratio from lateral and axial strain, or from the elastic and shear moduli, with typical material values.

Population Growth models population size over time with exponential or logistic growth, from growth rate, starting size, and carrying capacity.

Gravitational potential energy is the stored energy of an object resulting from its vertical position within a gravitational field (PE = mgh).

Power calculates mechanical or electrical power in watts.

Power Factor calculates power factor from real and apparent power or the phase angle, plus reactive power and correction capacitance for AC circuits.

PPM to Molarity converts ppm (parts per million) and molarity for a solute using its molar mass and the solution density, and to mg/L.

Primer Tm calculates melting temperature (Tm) of a PCR primer from its sequence using the basic (Wallace) and salt-adjusted GC methods.

Projectile Motion calculates range, maximum height, time of flight, and trajectory of a projectile from launch speed, angle, and initial height.

Protein Concentration calculates protein concentration from an A280 absorbance reading and the extinction coefficient (Beer-Lambert), or from a standard-curve method.

Protein Molecular Weight estimates protein's molecular weight from its amino acid sequence or residue count, plus mass-to-mole conversions.

Punnett Square generates a Punnett square for a monohybrid or dihybrid cross and calculates the genotype and phenotype ratios of the offspring.

QPCR Efficiency calculates qPCR amplification efficiency from the slope of a standard curve (E = 10^(−1/slope) − 1), with a quality assessment.

Validate a set of quantum numbers, finds the allowed values for a shell, and identify the subshell, orbital count, and electron capacity.

Raoult's Law calculates vapor pressure of a solution using Raoult's law from the solvent's mole fraction and pure vapor pressure, plus the vapor-pressure lowering.

Rate Law calculates reaction rate from the rate constant and reactant concentrations, or determine the reaction order from concentration-rate data.

RC Time Constant calculates RC time constant of a resistor-capacitor circuit and the charge or discharge voltage over time.

Redshift calculates cosmological redshift from observed and emitted wavelengths, and the recession velocity (classical and relativistic Doppler).

Relative Humidity calculates relative humidity from temperature and dew point, or from actual and saturation vapor pressure, plus absolute humidity.

Relativistic Kinetic Energy calculates relativistic kinetic energy of a fast-moving object (KE = (γ−1)mc²), and compares it to the classical ½mv².

Reynolds Number calculates Reynolds number of a fluid flow from density, velocity, characteristic length, and viscosity, and classify it as laminar or turbulent.

RLC Circuit calculates impedance, resonant frequency, and phase angle of a series RLC circuit from R, L, C, and frequency.

RMS Velocity calculates root-mean-square speed of gas molecules from temperature and molar mass, plus the average and most-probable speeds.

Rotational Kinetic Energy calculates rotational kinetic energy from the moment of inertia and angular velocity, and the total energy of a rolling object.

Rydberg Equation calculates wavelength of a hydrogen spectral line from the electron transition levels using the Rydberg equation.

Schwarzschild Radius calculates Schwarzschild radius (event horizon) of a black hole from its mass, with presets for a stellar black hole, Sagittarius A*, M87*, the Sun, Earth — and you.

Section Modulus calculates section modulus and moment of inertia of common beam cross-sections (rectangle, circle, I-beam, hollow), plus the bending stress.

Serial Dilution plans serial dilution: final concentration at each step, the dilution factor, and how much stock and diluent to use per tube.

Shear Modulus calculates shear modulus (modulus of rigidity) from shear stress and shear strain, or from Young's modulus and Poisson's ratio.

Shear Stress calculates shear stress from a force applied parallel to a cross-sectional area (τ = F/A), and solve for force or area.

Simple Harmonic Motion calculates period, frequency, position, velocity, and acceleration of simple harmonic motion for a mass-spring system.

Snell's Law calculates angle of refraction, index of refraction, or critical angle for light passing between two media using Snell's law.

Sound Intensity converts sound intensity and decibel level, add multiple sound sources, and see how distance reduces loudness.

Specific Gas Constant calculates specific gas constant of a gas from its molar mass (R_specific = R/M), with presets for air and common gases.

Specific Gravity calculates specific gravity (relative density) of a substance from its density and a reference (water or air), and converts to density.

Specific Heat calculates heat energy to change a substance's temperature (Q = mcΔT), with solutions for mass, specific heat, or temperature change.

Specific Impulse calculates specific impulse of a rocket engine from thrust and propellant mass flow, or convert between specific impulse and exhaust velocity.

Standing Wave calculates harmonic frequencies and wavelengths of a standing wave on a string or in a pipe (open or closed), from the length and wave speed.

Stefan-Boltzmann Law calculates radiated power of a blackbody or grey body from temperature, area, and emissivity (P = εσAT⁴).

Use mole ratios from a balanced equation to convert between reactant and product amounts in grams or moles.

Stokes' Law calculates drag force on a small sphere in a fluid and its settling (terminal) velocity using Stokes' law.

Strain calculates mechanical strain from the change in length and original length (ε = ΔL/L), as a ratio and a percentage.

Stress calculates mechanical stress from force and cross-sectional area (σ = F/A), and solve for force or area, in Pa, kPa, MPa, and psi.

Tension calculates tension in a rope or cable — hanging weight, two-rope angled support, or an Atwood machine — from the masses and angles.

Terminal Velocity calculates terminal velocity of a falling object from its mass, cross-sectional area, drag coefficient, and air density.

Theoretical Yield calculates theoretical yield of a product from the limiting reactant amount and the balanced-equation mole ratio.

Thermal Expansion calculates how much a material expands with temperature — linear, area, or volumetric expansion — from its expansion coefficient.

Thermal Stress calculates thermal stress in a constrained material from its Young's modulus, thermal expansion coefficient, and temperature change (σ = EαΔT).

Thrust-to-Weight Ratio calculates thrust-to-weight ratio of a rocket, aircraft, or vehicle from thrust and mass, and check whether it can lift off.

Time Dilation calculates relativistic time dilation from velocity — how much slower a moving clock runs — using the Lorentz factor.

Titration determines unknown concentration in an acid-base titration from the titrant volume and concentration and the mole ratio at the equivalence point.

Torque calculates torque from force, lever arm length, and angle, and solve for force or distance. Physics torque (τ = rF sinθ), not engine torque.

Torsion calculates torsional shear stress and angle of twist in a circular shaft from the applied torque, using the polar moment of inertia.

Trihybrid Cross calculates phenotype and genotype ratios of a trihybrid cross (three traits) using the forked-line method, with the 27:9:9:9:3:3:3:1 ratio.

Velocity calculates velocity, distance, or time using kinematics.

Von Mises Stress calculates von Mises equivalent stress from principal stresses or from a general stress state, and check yielding against a material's yield strength.

Water Hardness converts water hardness between units — ppm/mg-L as CaCO₃, grains per gallon, and degrees (German, French, English) — and classify soft to very hard.

Wave & Frequency calculates wave frequency, wavelength, period, or speed using v = f x lambda.

Wave Speed on a String calculates speed of a wave on a string from the tension and linear mass density, and solve for tension or density.

Wet Bulb Temperature estimates wet-bulb temperature from air temperature and relative humidity (Stull approximation), with a heat-safety interpretation.

Wien's Law calculates peak wavelength of blackbody radiation from temperature (Wien's displacement law), or the temperature from the peak color.

Wind Chill calculates wind chill (feels-like temperature) from air temperature and wind speed using the NWS wind chill formula, with a frostbite warning.

Young's Modulus calculates Young's modulus (elastic modulus) from stress and strain or from force, area, and length change, and solve for any variable.