Floating an Upside Down Bucket: Water Displacement Explained

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In summary, there is a discussion about water displacement principles and the weight required to sink an empty bucket that is filled with water. It is mentioned that if the bucket is placed upside down, trapping a 5Ltr volume of air, the weight needed to sink it is more than the weight of the water. However, the other person clarifies that the force is actually equal to the weight of 5 liters of water, thus disproving the previous statement.
  • #1
mrmike
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hi, I am after some help from a person with a understanding of water displacement principles.
On a small scale- if an empty 5 LTR bucket is floated on a body of water, it will float, if the bucket is filled with water it sinks.
But if the empty bucket is place upside down, thus trapping a 5Ltr volume of air, the weight required to sink the bucket is more than the weight of the 5 Ltrs of water, is this true, and is there a formula for working out the volume of Air trapped and what weight is required to sink it?
 
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  • #2
mrmike said:
But if the empty bucket is place upside down, thus trapping a 5Ltr volume of air, the weight required to sink the bucket is more than the weight of the 5 Ltrs of water, is this true, and is there a formula for working out the volume of Air trapped and what weight is required to sink it?
No, the force is equal to the weight of 5 litters of water.
 
  • #3


Hello,

Thank you for reaching out for assistance with your question about water displacement. I would be happy to provide some insight and explanation.

Firstly, your observations about the behavior of the bucket are correct. The principle of water displacement states that when an object is placed in water, it will displace (or push aside) an amount of water equal to its own volume. This is why the empty bucket floats, as it is displacing an amount of water equal to its own volume, making it less dense than the water.

When the bucket is filled with water, it becomes denser than the water and sinks. However, when the bucket is placed upside down, it traps a volume of air inside. This air acts as a buoyant force, pushing the bucket upwards. The weight of the bucket plus the trapped air is now less than the weight of the water that was previously displaced, allowing the bucket to float.

To answer your question about the formula for calculating the volume of air trapped and the weight required to sink it, it would depend on the specific dimensions and weight of the bucket. However, the general formula for buoyant force is Fb = ρVg, where ρ is the density of the fluid (water), V is the displaced volume, and g is the acceleration due to gravity. This formula can be used to calculate the buoyant force of the air trapped in the bucket, and the weight required to sink it would be equal to or greater than this buoyant force.

I hope this helps to clarify the concept of water displacement and the behavior of the upside down bucket. If you have any further questions, please don't hesitate to ask. Keep exploring and learning about the fascinating world of science!
 

What is water displacement?

Water displacement is the phenomenon that occurs when an object is placed in water, causing the water to be pushed aside and creating an upward force on the object.

Why does an upside down bucket float when placed in water?

An upside down bucket floats due to the principle of buoyancy. The weight of the water that is displaced by the bucket is equal to the weight of the bucket itself, creating a balance of forces that allows the bucket to float.

How does the shape of the bucket affect its ability to float upside down?

The shape of the bucket affects its ability to float upside down because it determines the volume of water that will be displaced. A bucket with a larger surface area will displace more water and therefore have a greater buoyant force, making it more likely to float upside down.

Can any object float upside down in water?

No, not all objects can float upside down in water. The object must have a density that is less than the density of water in order to float. If the object's density is greater than that of water, it will sink.

How does the density of the water affect the floating of the bucket?

The density of the water does not directly affect the floating of the bucket. However, the density of the water does affect the buoyant force acting on the bucket. If the water is more dense, the buoyant force will be greater, making it easier for the bucket to float upside down.

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