# Density question - can a heavy object float in water ?

• Yoann
In summary, as long as an object weighs less than the water it would displace if submerged, it will float. This means that even a big ball weighing 100kg with a diameter of 1 meter can float in water as long as its density is lower than water's, including any hollow areas. This is similar to how boats, which are heavier than 100kg, can float due to their lower density compared to water. The key factor is the density, not the total mass, when determining if an object will float in water.
Yoann
Would a big ball weighing 100kg with a diameter of 1 meter float in water?

I guess my question is, no matter how heavy an object might be, as long as it is less dense than water, it will float no matter what, right? Like even if that ball were made of a thick layer of steel (a few inches), as long as it is hollow/empty on the inside (and big enough so that its density is lower than water's), it would float, wouldn't it?

Thanks!

As long as the object weighs less than the water it would displace if submerged, it will float. So yes, as long as the density of the object, including any hollow areas, is less on average than water it will float.
http://en.wikipedia.org/wiki/Buoyancy

Boats can float and I'm pretty sure they are heavier than 100kg's

That's what I thought, thanks for the replies! (and the link to Wikipedia, Drakkith! It's helpful)

Gravitational said:
Boats can float and I'm pretty sure they are heavier than 100kg's
Okay, but a cubic meter of water is a thousand kg.

The key is the density, not the total mass. If you include the air inside the boat then it is less dense than water, therefore it floats.

## 1. Can a heavy object float in water?

Yes, a heavy object can float in water if it has a lower density than water. Density is the measure of how much mass is contained in a certain volume. If an object has a lower density than water, it will be able to displace enough water to float.

## 2. How do you determine the density of an object?

Density is calculated by dividing the mass of an object by its volume. The mass can be measured using a scale, and the volume can be measured by either calculating the dimensions of the object or by submerging it in water and measuring the displacement.

## 3. Can an object with a higher density than water sink?

Yes, an object with a higher density than water will sink because it will not be able to displace enough water to stay afloat. This is why heavy objects like rocks sink in water.

## 4. What is the relationship between density and buoyancy?

Density and buoyancy are inversely related. This means that as the density of an object increases, its buoyancy decreases. Buoyancy is the force that pushes an object up when it is submerged in a fluid, and it is determined by the weight of the displaced fluid. If an object is less dense than the fluid it is submerged in, it will experience an upward buoyant force and float.

## 5. Why do some objects float while others sink in water?

Objects float or sink in water depending on their density compared to the density of water. If an object is less dense than water, it will float. If it is more dense than water, it will sink. This is why objects like wood, which have a lower density than water, can float, while objects like metal, which have a higher density, will sink.

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