Description This video is an interactive lesson in calculating an atom’s mass and atomic number. Atoms consist of a nucleus containing protons and neutrons, surrounded by electrons in shells.

Medically reviewed by Suzanne Fisher, RD Key Takeaways Body mass index (BMI) is a calculation used to estimate your body fat.

Atomic Number and Atomic Mass: Get here the easy notes on atomic number and atomic mass for all the first 30 elements. Know how to calculate atomic mass using atomic number.

Calculate Your Body Mass Index online by using our special tool BMI calculator. The tool gives you an indication about your health, whether you are carrying healthy weight or not!

With that number known, we can solve the mass equation for the whole world. Every time you step on a bathroom scale, you're measuring the mass of the planet.