If I were asked the question of what weighs more, wither 1kg of Iron or 1kg of feather, the answer would be equal and that's because with mass, 1kg of anything is constant and this is because it is the measure of the quantity of matter which i contained in the body but this is not the same thing as weight. I hope I am not confusing you!
With Weight, it is the force exerted on the mass of an object by gravity. you see, the reason why 1kg of steel or iron will fall to the ground faster than a kg of feather is weight. So since we understand this, it will be right if we mention that depending on where we are, the weight of an object can differ based o gravity. On the moon, whatever you measure will be 161/2% the weight on earth because the gravity on the moon is 161/2% what it is on earth. Okay! We agree this is very possible comparing the gravity of earth and our moon but what if I tell you that it is possible for One thing to have different weight on earth?
Most of us have a different definition of what we call weight. We assume that weight is what we measure on a scale, those numbers that read up to some hundreds of kilograms or thousands of pounds but that is not weight rather they are mass. If the answers you get are in newtons then you are getting weight but if they are not, then it is mass that you are getting. So while a weight measures the force gravity puts on a mass, the number on the scale isn't for weight but for mass. So in simple terms, Mass is what makes up an object, weight is the gravitational pull on the object.
You see, when you weigh two different things on the same scale, in the same area, they are affected by the same influence of gravity but do you know that a kilogram of feather on the north pole weighs more than a kilogram of steel on the equator. First, earth is not flat, and also it is spinning which is what keeps half of the planet from becoming frozen. Because the earth isn't flat neither is it spherical, and it rotates, it means the equator gets to spin at about 460 meters per second and the earth is fatter at the equator and gravity gets weaker with distance.
When an object is farther to the center of the earth, couple with the centrifugal pull as a result of its rotation means that gravity at the equator 0.5% weaker than at the north and south poles. But this is not the only reason why gravity pull will change at different areas on earth, another reason is the unleveled ground on earth. Gravity where you are can be higher or lower depending on the rock in the crust beneath the feet. A good example is the increase in density in the crust beneath iceland and the Mid-Atlantic ridge compared to the indian ocean which means that gravity is more in the North Atlantic.
This is why the Tom and Jerry satalites exists so as to be able to help us have a definite gravity measurement on the planet. With this, we have been able to get that the place where we weigh the least is at the Peruvian Mountain known as Huascaran, while where we have the highest weight is on the Ocean near Northern Russia. When a ball is dropped on top of the peruvian mountain it would hit the ground 1.6 microsecond later than it would hit the ground in a place where gravity isn't heavy.
Reference
http://www.cleonis.nl/physics/phys256/equatorial_bulge.php
https://gracefo.jpl.nasa.gov/
https://www2.csr.utexas.edu/grace/publications/fact_sheet/4.html
https://physics.stackexchange.com/questions/203257
https://www.nsf.gov/news/classroom/images/Gravity.pdf
https://gracefo.jpl.nasa.gov/
https://www2.csr.utexas.edu/grace/publications/fact_sheet/4.html
https://physics.stackexchange.com/questions/203257
https://www.nsf.gov/news/classroom/images/Gravity.pdf