1. Measure the mass of an empty container 2. pour the desired liquid in to this container and wait for it to settle. 3. measure the mass of the container + liquid 4. subtract the empty container mass to find the liquid's mass Note: some scales have a tare feature (it defines a weight of zero), which you measure the container's mass, use the tare option, and then pour the liquid and wait for it to settle. Also, when you use a scale, in truth you measure weight. It then divides by the known gravity field to find a "weight" in kilograms, which we accept to equal the mass in kilograms. You only truly measure mass when using a balance. It compares the torque on the balance arm of the object's weight to the torque on the balance arm of a slide-able weight. A balance will record the same mass in any gravitational field.