- Forces
What is Weight?
Weight is a force caused by gravity. Because it is a force, it is also measured in Newtons (N). It is the gravitational force between the object and the Earth. An object will have a greater weight if it has more mass.
All over the world, people read the weight of objects with kilograms. That is not correct. It is done only because it is easy for people to grasp. The proper scientific unit of measurement is Newton, and it is written as N.
As mentioned on the previous page, the weight of an object is the same everywhere on earth because the object is under the same pull of gravity. In Space, there is no gravity, so the object will not even sit on the scale at all. It will just stay in suspense. Technically speaking, there is no weight in Space.
Weight is the vertical force exerted by a mass as a result of gravity. Gravity is a key concept here. Weight is dependent on it. In other words, it is the strength of the gravitational pull on the object.
Gravity on the Moon is less, and that means an object will weigh less on Moon than on earth.
An object’s weight (W) can be determined by the product of its mass (m) and the magnitude of the local gravitational acceleration (g), thus W = mg.
An object with a mass of 1 kg has a weight of about 10 N, everywhere on earth.
“Mass does not change whether it is measured on Earth or the ISS. Weight can change depending upon the gravitational pull such as on the Moon where weight is reduced to one-sixth that of on Earth.”
~National Aeronautics and Space Administration. https://www.nasa.gov/pdf/591747main_MVW_Intro.pdf last accesses Feb 2021
Apparent weight
Sometimes the scale can record the weight of an object and get it wrong. Here is a simple test: The next time you stand on a scale, you will notice that your weight will be slightly more if you try to jump on it. This is because you put more force downwards, in addition to the original force of gravity. This is apparent weight, and it is a measure of downwards force, not the weight from gravity.