What Causes an Object to Float?

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Discussion Overview

The discussion revolves around the factors that determine whether an object can float, specifically examining the roles of Archimedes' buoyancy principle and surface tension. Participants explore various concepts related to buoyancy, floating, and the influence of different liquids.

Discussion Character

  • Debate/contested
  • Conceptual clarification
  • Exploratory

Main Points Raised

  • Some participants propose that Archimedes' buoyancy principle and surface tension are the main concepts determining whether an object can float.
  • Others argue that surface tension may not significantly influence buoyancy, particularly in larger objects like boats.
  • A participant notes that surface tension can support small insects like water striders, but questions whether this constitutes true floating.
  • There is a discussion about the terminology of "floating" versus "buoyancy," with some suggesting that floating can refer to various factors that prevent submersion.
  • Some participants mention that the density of the object relative to the liquid is crucial for determining whether it will float or sink.
  • One participant raises the idea that the specific liquid's density also plays a role in whether an object floats, using examples like bricks in water and oil on water.
  • Another participant questions how much of the floating effect in small insects is due to surface tension versus displaced water.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the role of surface tension in floating. There are multiple competing views regarding the definitions of floating and buoyancy, as well as the factors influencing these concepts.

Contextual Notes

Terminology related to floating and buoyancy is discussed, with some participants acknowledging potential regional differences in word usage. The conversation also highlights the complexity of defining floating in various contexts.

NeoScience
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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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I don't think surface tension has much to do with it.
 
Water strider bug has surface tension to hold it up.
 
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.
 
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:
 
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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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.
 
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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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.
 

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