does weight of objects differ in water from air?

Question

is the weight of an object in water different from its weight in air

Answer 1

I'm sorry, i have to correct some of the misunderstandings posted above here.

THE WEIGHT DOES NOT, I REPEAT, DOES NOT CHANGE IN WATER. weight is a term in physics for the interaction of gravitational forces on a masseous object. Does the mass of the object change in water? NO. Does the mass of the earth change when an object enters water? NO. Therefore the weight is the same.

Why do objects feel lighter in water? the difference in net force is the answer. Weight still pulls down equally... However, the water creates a boyent force which counteracts a percentage of the weight (depending on the object submerged. roughly counteracts 40% for humans, different for other objects). In this way, while the weight is the same, the downward force of the object is less. That's the confusion point for almost everyone who's answered so far.

Answer 2

Yes.

Weight is different from Mass. Mass doesn't vary, you have the same MASS no matter where you go.

But WEIGHT is generally taken to mean "how hard are you held down" or "how much force is needed to lift you up.

So, consider a rubber balloon full of air. In air, it has weight, it falls to the floor. With a food scale, you can measure it.

If you put it under water, it tries to float to the surface. It has _negative_ weight.

Similarly, consider a block of wood with screws in it so it "just hangs there" in the bath tub, one inch below the surface. It's "weightless" it takes no force at all to move it up and down. But it still has MASS.

You measure mass using a BALANCE. you measure weight with spring scale.

Some people will define weight as "how hard gravity pulls on you." If you use that definition instead then the buoyancy of the water doesn't matter, and your weight is the same.

Answer 3

Weight is a measure of gravitational pull on an object's mass. Since the mass of an object doesn't change when submerged in liquid or air, the weight will change because of the action of the water on the mass which is called bouyency.

Every liquid/solution has a specific bouyency factor. Pure water offers less bouyency than salt water. Very salineated water offer more bouyency than lightly salieanated water.

So, even an apparently simple question like yours actually has quite a bit of nuance in the answers...

Answer 4

Yes. The simplest example of this is a rubber baloon filled with air. In air, the object will have a weight of maybe a few grams, however if you try to immerse it completely, it will have a NEGATIVE weight. The buoyancy (upward force) will be larger than the weight due to gravity. This is because the weight of the water that it is displacing is greater than the weight of the balloon, so the water wins in its quest to be pulled towards the earth.

Answer 5

Depends on your particular definition of "weight"...

However...If you take a 10 kilo mass and place it on a scale, whether in water ot not, it will still mass 10 kilos. The scale will also display a ten kilo difference between before and after, in water or not. That's mass.

For weight, that depends on the, pardon the pun, gravity of the situation. a ten kilo weight will always weigh 10 kilos in a 1G gravity field.

Answer 6

no...the mass of an object stays the same.. it is a conserved quantity, like energy...the apparant mass of an object in water becomes lighter due to buoyancy.. in other words.. the water is supporting some of the objects mass against gravity

Answer 7

yes the weight is different but the density stays the same because the density of water is different than air

Answer 8

Yes, actually, because water is denser than air, so the objects in it get "lighter".

Answer 9

OBJECTS IN WATER ONLY WEIGH 60% OF THEIR TOTAL WEIGHT.