Featured contributor PhD Applied Physics; former research associate at a national metrology lab.

Dr. Helena Ortiz

Senior Reviewer, Science & Engineering

0 calculators 0 articles Member since Jun 2026

About

Helena is the senior technical reviewer for physics, chemistry, and unit-conversion calculators. She is the last pair of eyes on every formula — checking constants, units, and edge cases against primary sources and standards bodies.

She holds a PhD in Applied Physics and previously held a research post at a national metrology lab.

Areas of expertise

Physics Chemistry Unit conversion Measurement standards

Education & credentials

BSc Physics — Universidad Complutense de Madrid
PhD Applied Physics — Stanford University

Sports

Wingate Anaerobic Peak Power from Load and Cadence Calculator

Estimates Wingate peak power: PP = Torque × ω = (load × 9.81 × wheel_radius) × (2π × peak_rpm / 60). Mean power ≈ 0.75 ×...

basic

947 4.2 1 min

Chemistry

Percent Ionic Character Calculator

Estimate the percent ionic character of a single bond from the electronegativity difference using Pauling's formula: %io...

basic

16,554 4.4 1 min

Physics

Einstein Rest Energy from Mass Calculator

Compute the rest energy contained in a mass via Einstein's mass-energy equivalence: E₀ = m · c². Reports the energy in j...

basic

4,820 4.1 1 min

Physics

Planck Spectral Radiance Calculator

Compute the spectral radiance B_λ(T) of a blackbody at wavelength λ and temperature T using Planck's law: B_λ = 2hc² / λ...

basic

8,009 3.9 1 min

Physics

Adiabatic Process Final Temperature from Volume Ratio Calculator

For a reversible adiabatic (isentropic) process on an ideal gas, the temperature scales with the volume ratio raised to...

basic

18,943 4.7 1 min

Physics

Gear Ratio Speed & Torque Calculator

Calculates gear ratio, output speed (RPM), and output torque from input speed, input torque, gear teeth counts, and tran...

basic

10,124 3.8 1 min

Physics / Mechanics

Simple Harmonic Motion Period (Mass-Spring) Calculator

Compute the period and frequency of a mass-spring oscillator undergoing simple harmonic motion from the mass m and sprin...

basic

24,544 4.5 1 min

Physics

Young's Double-Slit Fringe Spacing Calculator

Compute the spacing of bright fringes in Young's double-slit experiment from the wavelength of the light, the slit separ...

basic

3,332 4.9 1 min

Health

Child-Pugh Score Calculator

Calculates the Child-Pugh score for liver cirrhosis severity from bilirubin, albumin, INR, ascites, and encephalopathy g...

basic

15,136 4.0 1 min

Chemistry

Beer-Lambert Law Absorbance & Transmittance Calculator

Calculates absorbance, transmittance, and concentration in a Beer-Lambert spectrophotometry experiment from molar absorp...

basic

11,550 4.8 1 min

Health

Richmond Agitation–Sedation Scale (RASS) Score Calculator

Provides the RASS score interpretation: −5 (unarousable) to +4 (combative). Based on 3-step assessment: observation, ver...

basic

15,134 4.2 1 min

Health

Modified Fischer Score for SAH Vasospasm Risk Calculator

Applies the Modified Fischer Scale to CT findings after subarachnoid haemorrhage: Grade 1 (thin SAH, no IVH) to Grade 4...

basic

22,553 4.3 1 min

Showing 13 to 24 of 504 results

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Reviewed by Dr. Helena Ortiz

These calculators were technically reviewed by Dr. Helena Ortiz for accuracy.

Chemistry / Reactions

Equilibrium Constant Calculator

Compute the equilibrium constant K_c from the concentrations of two products (with stoichiometric coefficients 1) divide...

basic

5,060 4.0 1 min

Conversions / Length

Length Converter

Convert between meters, kilometers, miles, feet, inches, and yards.

Featured basic

4,964 4.2 1 min

Chemistry / Solutions

Combined Gas Law Calculator

Find the missing pressure, volume, or temperature using the combined gas law for a fixed amount of gas.

basic

5,360 4.2 1 min

Physics / Electricity

Capacitance Calculator

Compute the capacitance of a parallel-plate capacitor from plate area, plate separation, and the dielectric constant.

basic

12,524 4.1 1 min

Chemistry / Solutions

pOH Calculator

Compute pOH from hydroxide ion concentration and the matching pH at 25 °C.

basic

18,221 4.2 1 min

Ecology / Carbon Footprint

Carbon Footprint Calculator

Estimate your annual personal CO₂e footprint from home energy, driving, flying, and diet — with adjustable emission fact...

Featured basic

15,825 4.9 1 min

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Dr. Helena Ortiz

Wingate Anaerobic Peak Power from Load and Cadence Calculator

Percent Ionic Character Calculator

Einstein Rest Energy from Mass Calculator

Planck Spectral Radiance Calculator

Adiabatic Process Final Temperature from Volume Ratio Calculator

Gear Ratio Speed & Torque Calculator

Simple Harmonic Motion Period (Mass-Spring) Calculator

Young's Double-Slit Fringe Spacing Calculator

Child-Pugh Score Calculator

Beer-Lambert Law Absorbance & Transmittance Calculator

Richmond Agitation–Sedation Scale (RASS) Score Calculator

Modified Fischer Score for SAH Vasospasm Risk Calculator

Reviewed by Dr. Helena Ortiz

Equilibrium Constant Calculator

Length Converter

Combined Gas Law Calculator

Capacitance Calculator

pOH Calculator

Carbon Footprint Calculator