Difference between mass and weight

Chances are that you may have wondered about the difference between mass and weight, and it may surprise you to know that the same issue even got Newton thinking which led him formulating the laws of gravity. Mass is the total amount of material, be it your body or some other object and is often expressed in kg, grams, etc. Weight on the other hand, is the result of gravity acting on the said mass, which is why you would weigh less on the moon than you would, say on earth as the gravity on the moon is a lot less, compared to that of the earth’s own. This is the key difference between both the words.

Difference between mass and weight

The mass of the body does not change and it remains constant at all times; however, the weight of the body does change depending on the gravity in the immediate vicinity. This does bring an interesting question to mind – what happens to mass and weight when it comes to space and vacuum in particular? Well, as you may know, objects weigh almost nothing in space but before you assume that means that mass reaches zero in space, do realize that the mass would remain a constant. Since, in space, there is no gravitational force acting on the body, therefore you tend to float and weigh almost nothing. But if you measured the mass of your body, you will find that it still remains the same.

Which brings us to yet another fascinating aspect in the variation of mass vs. weight; as most of you know, black holes exert enormous gravitational forces on nearby bodies which eventually results in the said body collapsing into the black hole. But before it crosses the event horizon, the body, by definition should increase in weight, while the mass for the same remains the constant. So the question that you may want to ask is whether it is possible for a body to gain weight several times in excess of its own mass. As the body collapses into the black hole, it should but unfortunately, there is no technology yet available which will allow us to measure the weight of a body before it is eaten by the black hole. What we can do is extrapolate this information from a real-life phenomenon that takes place right here, on earth.

Tourists, who often visit the Great Pyramid of Giza, may be unaware of the fact that they would weigh just a little bit more when they are closer to the pyramid than when they are, a few km away. This is mainly on account of the fact that the pyramid has its own effect on gravity and as a result, you will weigh just a little bit more, at the base of the pyramid.

Now let’s get to the brass tacks – weight is as a result of the gravitational forces acting on the mass of your body and therefore it is a variable, unlike mass. Furthermore, weight can vary from place to place, depending on where you are located but it should not vary by that much unless you are right near an extremely massive object with a huge mass. When that happens, the body in question will exert its own effect on gravitational forces and should result in your weight increasing incrementally. Therefore, when you work out the math, you should be able to work out just how much you would weigh, and how much in excess of your mass, just before you get sucked into a black hole. Astronomy is an interesting subject, especially when discussing differences between mass and weight.

And in case you were wondering, the weighing machine registers your weight, which should be expressed as Newtons but instead, you end up getting the readout in kgs and pounds. The weighing machine actually measures your weight in full, which is it shows you the result of earth’s gravity acting on your mass. Earth’s gravitation stands at 9.8m/s2, so when you multiply your current mass by the same, you get your weight which is what the weighing machine does, each time you try it out. This is the basic difference between the two so the next time you weigh yourself on the machine, you may want to try working out your ‘mass’ based on the weight measurement you get, which should make for an interesting exercise in itself.

Leave a Reply