Why can an aluminum boat float?

  • Thread starter jarod
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In summary, an aluminum boat can float because it is made mostly of air, making its overall density less than that of water. This is similar to the concept of constructing a concrete "canoe" which, although not the most efficient watercraft, can still float due to its overall density. The overall density of an object is determined by its center of gravity and composition, which in the case of an aluminum boat includes the air inside its total volume.
  • #1
jarod
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We know that the density of Al is greater than the density of water, yet why can an aluminum boat can float?
 
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  • #3
jarod said:
We know that the density of Al is greater than the density of water, yet why can an aluminum boat can float?

If an Al boat puzzles you an Aircraft carrier must be simply amazing.
 
  • #4
An aluminum boat floats, jarod, because it is made mostly of air! (by volume)
 
  • #5
Integral said:
If an Al boat puzzles you an Aircraft carrier must be simply amazing.

when i was in school, i remember these civil engineering departments like to construct, as a demonstration, a concrete "canoe" and paddle that in a lake or river. not the most efficient watercraft, but it floats.
 
  • #6
russ_watters said:
An aluminum boat floats, jarod, because it is made mostly of air! (by volume)

Is it what you meant was the overall density of the aluminum boat is less than the density of water?
 
  • #7
yeah I've heard about making a concrete slab float, very difficult to do, we really had headaches when this problem was given to us...
 
  • #8
yes actually the overall density of an object is related to center of gravity and composition of the boat, since the boat is not the Al. part only but also the air inside the total volume, this what makes it lighter than water
 

1. How does an object float?

When an object is floating, it means that it is being supported by the buoyant force of a fluid (such as water or air) that it is submerged in. This buoyant force is caused by the displacement of the fluid by the object. If the weight of the object is equal to or less than the buoyant force, it will float.

2. Why do some objects float while others sink?

Whether an object floats or sinks depends on its density compared to the density of the fluid it is submerged in. If the object is less dense than the fluid, it will float because the buoyant force is greater than its weight. If the object is more dense than the fluid, it will sink because the buoyant force is less than its weight.

3. Can an object float in any type of fluid?

Yes, an object can float in any type of fluid as long as its density is lower than the density of the fluid. For example, a helium balloon can float in air because it is less dense than air, and a boat can float in water because it is less dense than water.

4. What factors can affect an object's ability to float?

Several factors can affect an object's ability to float, including its density, shape, and size. Objects with a larger surface area relative to their weight tend to float better because they displace more fluid. Temperature and pressure can also affect the density of a fluid, which can impact an object's ability to float.

5. Can the buoyant force change over time?

Yes, the buoyant force can change over time if there are changes in the density of the fluid or the object. For example, as ice melts and turns into liquid water, its density decreases and the buoyant force on it will change. Additionally, if an object is compressed or expands, its density can change, affecting the buoyant force on it.

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