The weight of an object, or of an amount of matter, is typically measured with an instrument such as a spring scale. The scale includes a spring which provides a force to oppose the gravitational force on the object which is being weighed. The gravitational force pulls down, the spring pushes or pulls upwards. Typically, the scale has a readout which gives not the weight (which is a force) but rather the mass of the object. Spring scales are made with the assumption that they are being used on the surface of the Earth. If a spring scale was taken to the Moon it would give a misleading reading.