In science and engineering, the weight of an object is the force acting on the object due to gravity. The unit of measurement for weight is force, which in the International System of Units (SI) is the newton. For example, an object with a mass of one kilogram weighs about 9.8 newtons on the surface of the Earth and about one-sixth as much on the Moon. Although weight and mass are scientifically distinct quantities, the terms are often confused with each other in everyday use (i.e., comparing and converting force weight in pounds to mass in kilograms and vice versa).