U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Physical Measurement Laboratory

Office of Weights and Measures

Measurement League: Guardians of the SI Superhero Card Set

Black and White graphic. Left side has black images of scales, rulers, SI logo. Right side has white images on black background of same items. The middle of image has a gray cirle with EDUCATION in black letters.
Keywords:Ampere, candela, electric current, error, SI, kelvin, kilogram, length, mass, meter, metric, mole, temperature, time, second, uncertainty
Audience:Students, educators, parents, public, technology coordinators, outreach ambassadors, formal, informal
Grade Level:3rd to 8th
Subjects:Art, biology, chemistry, life science, Earth science, engineering, environmental science, mathematics, physical science, physics, STEM, technology
Collage of Guardians of SI Superheroes
Credit: ©2020 U.S. Secretary of Commerce. All Rights Reserved.

 

 

 

SI Superhero Card Set
Edition: 2021

 

 

 

 

Summary

This digital resource features profiles for each of the Measurement League: Guardians of the SI superheroes, dedicated to the fight against uncertainty, imprecision, and inaccuracy and to improving the quality of our lives and the things we build. The superheroes include the following: Mole, Professor Second, Monsieur Kilogram, Ms. Ampere, Dr. Kelvin, Meter Man, and Candela. Each card in the set lists a different superhero’s name, picture, symbol, and the measurement unit they represent. The card set provides an entertaining way to learn more about the International System of Units (SI).

Did you know that you can obtain a free set of metric education resources for use in your classroom? Contact the NIST Metric Program at TheSI [at] nist.gov (TheSI[at]nist[dot]gov) and include your name, school, subject, grade level, phone number, and U.S. mailing address. Publication requests may also be made using the OWM Contacts System. The NIST SI Teacher Kit contains a curated collection of instructional measurement resources. A metric conversion card is a valuable tool for science, technology, engineering, art, and math (STEAM) classrooms.

Learning Objectives
  • Describe the seven SI base units.
  • Recognize SI base unit definitions.
Materials

Digital file.

Safety

Use caution when handling paper edges and scissors to prevent injury.

Teaching Tips
  • Use the Top 10 Tips for Teaching the Metric System.
    • Make measurements with metric tools. Measurement concepts are meaningfully established through hands-on activities. Application, not memorization, is the key to success! The SI is easy to learn when taught using metric tools.
    • Practice building proficiency and confidence in making measurements. Measurement involves doing.
    • Develop reference points. How long? How big? How small? It’s important for students to gradually develop an intuitive feeling for the magnitude of commonly used metric units, including the millimeter (mm) and centimeter (cm).
    • Use an interdisciplinary approach. Bring the SI into classrooms at every opportunity, including during instruction in language arts, fine arts, social sciences, industrial arts, vocational technologies, consumer studies, and physical fitness.
  • Explain the SI base units, unit definitions, and prefixes.
  • Discuss how each base unit is derived from a combination of defining constants.
Classroom Connections
Student Activities and Learning Aids
Videos
  • Graphic of League of SI Superheroes
    Credit: J. Wang and B. Hayes/NIST ©2020 U.S. Secretary of Commerce. All Rights Reserved.

    Videos. Comic book-style video animations, available on the NIST YouTube Channel.

    • Episode 5: Late Notice (08:29): What begins as a scramble to catch the school bus becomes an epic journey through the history of timekeeping—from sundials to atomic clocks.
    • Episode 4: Two Truths & a Lie (05:29): After rescuing Monsieur Kilogram and capturing Major Uncertainty, our Superheroes take a break and play a game of "Two Truths & a Lie."
    • Episode 3: Mass Hysteria! (04:18): The nefarious Major Uncertainty has kidnapped Monsieur Kilogram, putting the world’s measurements of mass in jeopardy.
    • Episode 2: Running Out of Time! (04:07): The SI Superheroes battle archvillain Major Uncertainty in a race to keep the world's satellite navigation system "on time."
    • Episode 1: Desperate Measures! (03:07): The SI Superheroes use the power of measurement to help a stranded soccer player get home.
    • The Revised Avogadro Constant (0:14): The Mole reviews the revised number for the Avogadro Constant with Monsieur Kilogram.
Educator Guides and Professional Development

EXPLORE THE METRIC PROGRAM

Becoming Familiar with SI | Everyday Estimation | Metrication FAQs | Prefixes | Metric Kitchen | SI Education and Training | SI Publications | Understanding Metric | Writing with Metric Units | National Metric Week | NEST-R (STEM Registry) | NIST Education Resources

Metrology, Metric and Weights and measures

Contacts

Created July 13, 2022, Updated August 11, 2026
Was this page helpful?