Heavyweight, lightweight, overweight, slender. Small, tall, vertically impaired, “how’s the weather up there?” Gifted, average, 700 math/600 verbal, rocket scientist. Gorgeous, handsome, hunk, babe.

Humans like to measure things. Whether it is our body size, height, IQ or looks, everything seems to be fair game.

Physics will teach you to measure even more things. For example, quantities such as displacement, velocity and acceleration are crucial to understanding motion. Other topics have yet more things to quantify: Mass and period are concepts required to understand the movement of planets; resistance and current are used for analyzing electric circuits. Just as you have developed a vocabulary for the things you measure, so have physicists.

There are many different units for measuring different properties. It is possible to go all the way from A through Z in units: amperes, bars, centimeters, dynes, ergs, farads, grams, hertz, inches, joules, kilograms, liters, meters, newtons, ohms, pascals, quintals, rydbergs, slugs, teslas, unit magnetic poles, volts, webers, x units, years, and zettabars. (OK, we had to stretch for X, but it is a real unit.)

Physicists have so many units of measure at their disposal because they have plenty to measure. Physicists use amperes to tell how much electric current flows through a wire, “pascals” quantify pressure, and “teslas” are used to measure the strength of a magnetic field. If you so desired, you could become a units expert and impress (or worry) your classmates by casually noting that the U.S. tablespoon equals 1.04 Canadian tablespoons, or deftly differentiating between the barrel, U.K. Wine, versus the barrel, U.S. federal spirits, or the barrel, U.S. federal, all of which define slightly different volumes. Or you could become an international sophisticate, telling friends that one German doppelzentner equals about 77,162 U.K. scruples, which of course equals approximately 101.97 metric glugs, which comes out to 3120 ukies, a Libyan unit used for the sole purpose of measuring ostrich feathers and wool.

Fortunately, you do not need to learn units such as the ones mentioned immediately above, and you will learn the others over time. Textbooks like this one provide tables that specify the relationships between commonly used units and you will use these tables to convert between units.