I also bought a 100 gram weight to calibrate the scale.
The first thing I did was weigh some coins. A Nickel is supposed to have a mass of 5 grams (here’s a page that lists the mass of different coins). All the Nickels I weighed had slightly different masses. Same with Pennies and Half Dollars.
I also weighed Bicycle playing cards. Each card has a mass of about 1.75 grams. I weighed all 26 red cards: 45.51 grams. The black cards came in at 45.57 grams. The four Aces had a combined mass of 7 grams on the nose. Would the Tens weigh more, since they have more ink than the Aces? I measured them: 7.03 grams. I tried a different deck. Aces: 7.03 grams. Tens: 7.03 grams. I’d love to weigh these on a 0.001 gram scale!
This scale has already paid for itself by amusing me for an hour. I hope it lasts a long time for its intended purpose.