Is clear water buoyant or turbid water buoyant?

The example given by the superior brother is incorrect, the title is said to be a turbid liquid, and the salt water is a solution and not a mixture, even if the example given is correct, the younger brother thinks that the above answer is also wrong.

We all know that the condition for an object to float is that the density of the object is less than the density of the solution, and the greater this density difference, the greater the buoyancy.

Looking at the title again, the cause of turbidity is that the solute in the dissolution is difficult to dissolve, and the insoluble solute is suspended in water, which means that the density of the solute is less than the density of the dissolved water.

One is pure water. One is that the density of the aqueous solution is smaller than that of water, and the overall density of the former is greater than that of the latter. So the buoyancy in the clear water is greater. In addition, if you compare it from the gravity of the discharged liquid, the former is also greater than the latter.

The amount of buoyancy experienced by an object in water depends on the gravitational force of the water it dispels, and under the same conditions, if the volume of water discharged by the object is the same, then the gravity of turbid water is greater than the gravity of the same volume of clear water. If the object is floating in either clear water or turbid water, then the buoyant force exerted by both types of water on the object is equal and equal to the gravitational force of the object.

It depends on the density comparison of suspended particles and water.

If it is in a turbid state, the buoyancy is high if the density of suspended particles is large, and the opposite is true if the density of suspended particles is small, and the same is unchanged.

Here's how I understand your statement:

If it is said that the buoyancy of the object in clear water and turbid water is the same, it can be divided into the following situations:

1.If the object floats in both clear and turbid water, or if it floats in turbid water suspended in clear water, then the buoyancy received by the object in both types of water is equal to its own gravity.

2.If the object sinks in clear water and floats or levitates in turbid water, then the buoyancy of the clear water (less than gravity) is less than the buoyancy (equal to the gravitational force of the object) in the turbid water.

3.If the object sinks in both clear and turbid water, then the buoyancy in both types of water is less than its own gravity, and the buoyancy in turbid water is generally greater, because the density of turbid water is generally greater than that of clear water.

Turbid water is denser, so it will be more buoyant.

Just like salt water is more buoyant than fresh water. Just because of the high density of salt water.

It's more cloudy, it's buoyant!!

There is not much difference in size. Can be ignored.

Developing the habit of constantly searching for the essence of the problem is very beneficial to learning physics well. In secondary school, this kind of pursuit does not have to be rigorous and cannot be rigorous, but it is essential for us to have a deep understanding of physics concepts.

Buoyancy is not gravity, butBuoyancy is created without gravity。Imagine that in weightlessness, the liquid will be isotropic.

Naturally, there is no buoyancy. It can be said that without gravity, there is no buoyancy. It is under the action of gravity that the liquid has a tendency to move downward, which creates the pressure inside the liquid; At the same time, due to the fluidity of the liquid, the internal pressure of the liquid at the same depth is equal in any direction.

An object immersed in a liquid is necessarily affected by the liquid on the immersion surface"Squeezing"The strength of this extrusion is not equal at different depths, and the greater the depth, the greater the extrusion, resulting in the upward extrusion being greater than the downward extrusion, and finally forming buoyancy.

Buoyancy can also be understood from a different perspective. Both liquids and objects under the action of gravity"Hopefully"Occupy the lower position as much as possible. As long as an object is immersed in liquid, whether it is submerged or not, as long as it occupies a part of the space that would otherwise be liquid, it means that the object is successful"Squeeze it out"a portion of liquid.

During this squeezing process, the object needs to exert a downward force on the liquid, which then produces an upward reaction force on the object.

Isn't that exactly buoyancy?

For gas buoyancy, the situation is similar to that of liquids, and it can be understood in contrast。The difference is that the density of gases is much smaller than that of liquids, and gases can be seen as a kind of extraordinary"Thin"of liquids; In addition, the density of liquids is generally considered to be a fixed value, while the density of air decreases with height.

It must be pointed out that the above understanding is not rigorous, and the generation of buoyancy also involves a variety of factors such as molecular forces, but at the junior high school level, this understanding is sufficient.

With the above understanding, we can look at a typical question:

Determine the buoyancy of the bridge pier.

In many books, there are two in the picture above"Bridge piers"are not buoyant because their lower surface is inserted into the dirt and is not subjected to the upward pressure of water on them. And I personally think that such an answer is wrong.

In Figure A, the pressure on the sides of the piers is horizontal and balanced, which does not lead to buoyancy. There is no water on the lower surface, and indeed there is no upward pressure. However, the upper surface of the bridge is submerged in water, and the pressure is downward, so the pier armor is subjected to downward buoyancy.

Since buoyancy is generated by the difference between the upper and lower pressures, why can't the downward pressure be greater than the upward pressure? An object that floats on the liquid surface has no liquid pressure on the upper surface and the buoyancy force comes completely from the lower surface, then the object inserted into the container, the lower surface has no pressure while the upper surface has, and the buoyancy force comes completely from the upper surface, so it is downward.

In Figure B, the pressure on the side of the pier is obliquely upward, balanced with each other in the horizontal direction, and there is an upward resultant force in the vertical direction. The specific magnitude of this upward force is related to the length and angle of the part of the pier in contact with the water, and may be greater than or equal to the downward pressure on the upper surface of pier B, so the buoyancy force on the pier in Figure B cannot be determined.

This is a physical principle, because there is a pressure difference between the top and bottom of the water, which makes the object float, and it has a lot to do with the weight of the things in the water and the density of the water.

Buoyancy occurs when an object immersed in a liquid (or gas) is subjected to the difference in pressure between the upper and lower surfaces of the liquid (or gas). It mainly looks at the lower part of the object to indicate whether it is subjected to the pressure exerted by the liquid. For example, the lower surface of the pier is deeply trapped in the silt and is not affected by buoyancy.

This situation is because water also has density, and when the density of water is greater than the density of the object, the object floats on the surface of the water.

The pressure of the water is related to the buoyancy of the water.

For an object immersed in water, the water will produce pressure and pressure on all surfaces of the object, and the pressure and pressure on each surface of the object in the water are related to the depth (p pgh), so the pressure on the object at the deeper position is greater, so that the resultant force of the pressure of the water on the surface of the object is always vertically upward, which is the reason for the buoyancy force.

Taking a cube-shaped object in water as an example, the water has pressure and pressure on its upper, lower, left, right, front and back six surfaces, and the pressure and pressure of the water on the front and rear sides and the left and right sides are balanced and can be counteracted, that is, the resultant force of the pressure of the water on the four sides is 0, and the pressure on the upper and lower surfaces will be greater than the upper surface due to the difference in depth in the water, and the pressure on the two surfaces is the same, their net force is not 0, and the direction is vertical upward, The resultant force of the whole object, i.e., the buoyant force, is equal here to the net force of the pressure of water on the upper and lower surfaces, and the direction is vertical and upward. The buoyancy of other irregular objects in the water is also caused by the combined force of the pressure exerted by the water on the surfaces of the object.

The buoyancy of salt water is greater than that of clear water One Sunday, my mother took out an egg, a packet of salt, and a large cup and said to me to do an experiment.

My mother first asked me to fill the cup with water and then put the eggs in the water, and the eggs sank. Then my mother asked me to put salt in the water, I put a spoonful of salt and nothing moved, my mother told me to put more salt, I put three spoonfuls of salt in a row, stirred it with a spoon, only to see the egg slowly stand up, and finally floated up. Then my mother told me a story about a captive who had not drowned in the Dead Sea, and made me understand that the specific gravity of salt water is greater than that of clear water, so the buoyancy of salt water is greater than that of clear water.

This experiment made me understand that my knowledge is like an ordinary drop of water, and there are a lot of knowledge that I don't understand.

Water is liquid, and as long as it is liquid, it is buoyant.

If something sinks, it means that it is denser than water.

Because there is gravity in liquids, pressure is generated, and experiments have shown that the pressure of liquids is p= gh, which is proportional to the depth and is transmitted in all directions.

If the stone is put into the liquid, the upper surface of the stone is subjected to the total pressure downward, and the lower surface of the stone is subjected to the total pressure upward, but because the average depth of the lower surface is deeper than the average depth of the upper surface, the upward pressure on the lower surface is greater, and the pressure on the upper surface is small, which forms a pressure difference, and the resultant force is buoyant, and the direction is upward. Therefore, buoyancy is caused by the pressure difference between the object immersed in the liquid.

To simplify it, if a square stone block is put into a liquid, assuming the area of the upper and lower surfaces is s, the density of the liquid is , and the depths of the upper and lower surfaces are h1 and h2 respectively, then the pressure on the upper and lower surfaces is:

f1=p1s=ρgh1s

direction down) f2 = p2s = gh2s

direction upward) pressure difference f = f2-f1 = gs (h2-h1) = f buoyancy.

Direction upward) buoyancy is produced due to the pressure difference between the upper and lower surfaces of the object, when this pressure difference is greater than the gravitational force of the object, it floats up, and when it sinks when it is less than the gravitational force of the object, it is equal to the time of suspension.

Buoyancy occurs because an object immersed in a liquid or gas is subjected to the difference between the upward and downward pressure of the liquid or gas on the object.

The pressure on the lower surface of the object in the liquid is greater than the pressure on the upper surface of the liquid, so the net force is f up - f down, because there is pressure inside the liquid in all directions, then the upper surface of the object is subjected to a downward pressure given to it by the liquid, and the lower surface of the object is subjected to an upward pressure given to it by the liquid.

Since in the same liquid, the greater the depth, the greater the pressure, so the pressure on the lower surface of the object is obviously greater than the pressure on the upper surface of the object, so it is f up - f down (theoretical derivation).

An object floating on the surface of a fluid or submerged in a fluid is subjected to the upward resultant force of hydrostatic pressure in all directions. Its magnitude is equal to the gravitational force of the fluid being dislodged by the object. Within a liquid, the pressure is different at different depths.

The depth of immersion in the liquid on the top and bottom of the object is different, and the pressure on the lower part of the object is greater than that of the liquid, and the pressure is also greater, which can prove that the buoyancy is equal to the difference between the upward and downward pressure of the liquid on the object. For example, if the gravity of a stone is greater than its weight in the same volume of water, it will sink to the bottom. The gravity of driftwood or the hull of a boat is equal to the weight of the water discharged by the part of the boat that it is immersed in, so it floats on the surface of the water.

The weight of the balloon is less than the gravity of its same volume of air, that is, the buoyancy is greater than the gravity, so it will rise. This force of immersion in water or air and the force of water or air pushing the object upwards is called "buoyancy". For example, a bucket of water from a well is lighter before it leaves the surface than after it leaves the surface, because the bucket is buoyant by the water.

Not only water, but all liquids such as alcohol, kerosene, or mercury are buoyant to the objects immersed in it. All liquids are the same. Of course, objects immersed in gases (which are fluids like liquids) are also subject to buoyancy.

Or take a look at the references

If an object (a regular object) is placed in water, the pressure at two points on the left and right sides of the same horizontal line is equal, and the surface area is also equal, so the pressure of water on both sides is also equal, and the net force is 0; However, the pressure at each point on the upper and lower surfaces is unequal, and the surface area is equal, so the pressure on the lower surface is greater than that on the upper surface, resulting in a pressure difference, and the resultant force of these two forces is upward, that is, buoyancy.

This is related to the pressure of the liquid, and the difference between the upward and downward pressure of the liquid creates an upward force.

Buoyancy refers to the difference in pressure between the upper and lower surfaces of an object in a fluid, including liquids and gases.

Any object placed in water has an upper and lower surface, and the pressure of the water on it is different.

This is because water is denser than air.

The root cause is gravity. The liquid state produces pressure under the action of gravity, and the pressure of the object in the liquid is different from place to place, and the algebraic sum of all the pressures experienced is not zero, so buoyancy is also generated.

The simple calculation is that the pressure on the upper part of the object is small, and the pressure on the lower part is strong, resulting in an upward pressure difference, which is converted into a pressure difference is the buoyancy force.