AI Tutor
Imagine opening a weather report and seeing this: "At 0600, air temp was 14∘C14^\circ\text{C} with Ξ”T=βˆ’3∘C/hr\Delta T = -3^\circ\text{C}/\text{hr}, while PM2.5β‰ˆ35 μg/m3\text{PM}_{2.5} \approx 35\,\mu\text{g}/\text{m}^3."
It looks like secret code, but scientists use technical symbols and units as shorthand to pack massive amounts of exact information into tiny spaces.
Once you know the rules behind these notations, you can translate any dense technical passage into plain English in seconds.
How do small numbers tucked at the bottom of letters completely change what a substance is?

Subscripts and Chemical Formulas

In science writing, a chemical formula uses letter abbreviations from the Periodic Table to show which elements make up a substance.
A subscript is a small number written just below the line of text, and it tells you exactly how many atoms of the element right before it are locked into that molecule.
If there is no subscript after a letter, like the O\text{O} in H2O\text{H}_2\text{O}, it always means there is exactly one atom of that element.
What about when numbers appear in front of the formula instead of below it?

Subscripts Versus Coefficients

A coefficient is a regular-sized number placed in front of an entire formula, telling you how many separate molecules you have.