What cause an object to float?

In summary, Archimedes' principle states that an object will float if it displaces more water than it takes up. Surface tension also plays a role in determining if an object can float.
  • #1
NeoScience
4
0
From what I gather so far, 2 main concepts determine if an object can float or not: 1) Archimede's buoyancy principle 2) Surface Tension.

Is the above reasoning correct? Are there any other concept?
 
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  • #2
I don't think surface tension has much to do with it.
 
  • #3
Water strider bug has surface tension to hold it up.
 
  • #4
I stand corrected.

I don't think the buoyant force would act on that bug would it?

If a body displaces fluid then I don't think surface tension would have much of an effect, for example in a boat.
 
  • #5
Actually, it does. If you want to have some fun with water bugs, just put a few drops of dish detergent beside them. Poof... straight down. :biggrin:
 
  • #6
An object that sits on top of a surface of a liquid due to surface tension is not floating. The word "floating" is referring specifically to buoyancy. It's right there in definition #1.

A water bug is standing on the water, not floating in it.
 
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  • #7
Oops... another terminology problem. :redface:
While 'buoyancy' refers to Archimedes, I always took 'floatation' to be a combination of various factors that keep an object from submerging. The vanes of a hydrofoil, for instance, are not buoyant... but they 'float' when an appropriate speed is achieved.
 
  • #8
Where are you from, Danger (your profile says the Twilight Zone, so I'm guessing Canada?)? It could be geogrphical differences in word usage. I wouldn't say any non-displacement vessel floats when it is in that mode (including speedboats).
 
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  • #9
Yeah, it's probably regional. We use the term for lots of different circumstances, such as a car at the top of its suspension travel or a pool ball rolling too far. 'Skating' is used in the same context.
 
  • #10
Well, wait - the word "float" has different definitions that don't all have to do with the concept of buoyancy - or even liquids. It has forty definitions. You can "float" an idea too, but that may be figuratively connected to the concept of buoyancy...

It is also a tool for polishing marble (36).

Maybe I'm just being pedantic - I'll ask a non-science type what they would say. Trouble is, I'll probably have to explain what a hydrofoil is...
 
  • #11
Naw, don't put yourself out; I concede the point. I was just explaining my sloppy use of the word. :biggrin:
 
  • #12
:cool: look, if an objects density(or volume,not sure which.Think it density.) is lower than 1, no matter what it is, it will float. its all about buoyancy:cool:
 
  • #13
Doesnt it depend on the liquid it is trying to float in. The less dense object will float and the denser will sink, so since a brick is denser than water it sinks, likewise oil poured into water floats because it is less dense. I had always thought that is the main principle behind it. Is this correct?
 
  • #14
In the case of the water bug or mosquito, it causes the "skin" of the tension layer of water to displace other water (small depressions in the water). I'm not sure how much of the "floating" for the water bug is due to displaced water and how much to just the surface tension.
 

1. What is the concept of buoyancy?

Buoyancy is the upward force exerted by a fluid on an object that is partially or fully immersed in it. It is a result of the difference in pressure between the top and bottom of the object.

2. How does the density of an object affect its ability to float?

An object will float if its average density is less than that of the fluid it is submerged in. This is because the upward force of buoyancy is greater than the downward force of gravity on the object.

3. Why do some objects float while others sink?

The buoyant force acting on an object is determined by its shape, size, and density. If the buoyant force is greater than the weight of the object, it will float. If the weight is greater, the object will sink.

4. How does the volume of an object affect its buoyancy?

The volume of an object is directly related to its buoyancy. A larger volume will displace more fluid, resulting in a greater buoyant force. This is why larger objects, such as ships, can float more easily than smaller objects.

5. What role does gravity play in an object's ability to float?

Gravity is the force that pulls objects towards the center of the Earth. When an object is placed in a fluid, the force of gravity acting on it is opposed by the upward force of buoyancy. If the buoyant force is greater, the object will float, but if the gravitational force is greater, the object will sink.

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