more to the fun:
a cup of liquid weights differently depending on the type of liquid. A cup of milk weight more than a cup of plain water, for example.
a cup of flour weights differently depending, too. A cup of whole weight flour weights more than a cup of bleached AP, for example.
If you have a scale, I hope it is electronic and accurate. They are priced under $50 now, for both been electronic and accurate. Sure thing, you can have a $300 electronic and accurate scale like mine’s but just paying for the looks basically =)
Therefore: scale, electronic, and accurate, I suggest you measure EVERYTHING by weight, and in grams. EXCEPT, minute volumes like vanilla, salt, and creme or tartar, I rather do by volume (spoon measures), but when I bake large batches, I measure by volume and then weight it, too.
You would need a laboratory scale, for thousands of $, to measure minute volumes by weight! Rose has one!