It allows people in different places and different countries to use the same units, avoid mistakes and understand each other more easily. The common base 10 of all units makes it easier and has more accurate calculations that are made without cumbersome conversion factors.
Add 1 tsp. of vinegar to the canister at a time, filling it almost to the top. You need to add as much vinegar to the canister as possible without the vinegar and the baking soda coming into contact when you later snap the lid onto the canister. Depending on the exact canister, this may be around 5 tsp.
