How can you measure the volume of a floating irregular object?

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To measure the volume of a floating irregular object, submerging it in water to determine the volume of displaced water is a valid method, as this volume corresponds to the object's volume. Alternative methods include using a denser fluid, like petrol, to facilitate submersion without the need for external pressure. Care must be taken to account for the volume of any tool used to submerge the object, ideally employing a thin implement for precision. The discussion emphasizes the importance of accurately measuring displacement to ensure correct volume calculations. Overall, the submerged volume directly reflects the object's volume, regardless of density differences.
arjose
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Homework Statement


How does one experimentally measure an irregular object's volume given that said object floats on water?

The Attempt at a Solution


It seems to me that the simplest solution to this is to submerge the whole object by pressing down on it to the point that only the object is submerged. I'm thinking that the volume of displaced water would equate to the volume of said object, regardless of densities or forces being applied. Am I correct?
 
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arjose said:

Homework Statement


How does one experimentally measure an irregular object's volume given that said object floats on water?

The Attempt at a Solution


It seems to me that the simplest solution to this is to submerge the whole object by pressing down on it to the point that only the object is submerged. I'm thinking that the volume of displaced water would equate to the volume of said object, regardless of densities or forces being applied. Am I correct?

Yeah, that's correct. The volume occupied by the submerged object was previously occupied by water.
 
cepheid said:
Yeah, that's correct. The volume occupied by the submerged object was previously occupied by water.
Thank you for verifying that.
 
Or, perhaps find some other fluid that the material is more dense than, say petrol or similar?
 
sjb-2812 said:
Or, perhaps find some other fluid that the material is more dense than, say petrol or similar?
Haven't thought of it that way. Makes sense though. Any other fluid that's less dense than water should do the trick of submerging the object. Thanks for that.
 
If you press the object down under the water, you must take into account the volume of whatever you are pressing it down with! You might want to use something very thin, like a needle but then it becomes difficult to hit the exact center.
 
The book claims the answer is that all the magnitudes are the same because "the gravitational force on the penguin is the same". I'm having trouble understanding this. I thought the buoyant force was equal to the weight of the fluid displaced. Weight depends on mass which depends on density. Therefore, due to the differing densities the buoyant force will be different in each case? Is this incorrect?

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