Why are planets, water droplets, etc. spherical?

As for the original doubt, it now seems that it may only be due to the influence of simple intermolecular forces. The reason why it is spherical by intermolecular forces is probably because when it has edges and corners, it will be worn out or subjected to greater force, causing it to be flattened. Water is most intuitive because it is liquid.

At the time of the birth of protogenitor cell bacteria, many of them were spherical because it was the easiest to maintain the spherical shape of the water droplets, and although it has not been verified, it is believed that the earlier the bacterial cells, the more spherical the bacterial cells are, and the more round they are. However, due to the adaptation to various environments and various functions, the form has changed accordingly. As for the planets, there are intermolecular forces (...).Eh, it should be said that gravity) has the greatest effect on the overall form, so although it is solid, it is still spherical.

As for the meteorite impact, the impact was too small. Probably the most influential other aspects are the movement of the earth's crust, such as the formation of the Himalayas. But there is no such thing as an absolute shape in the world.

Because of the action of surface tension, the liquid that is not affected by the external force can form a round shape. Because for an object of a certain volume, the surface area of the spherical surface is the smallest. As a result, the water droplet molecules always try to move closer together, thus reducing the surface area and thus forming a round shape

The spherical shape of the planet is due to the influence of gravity (the exact process is not understood), but the gravitational force must be large enough that the asteroid may not be spherical. The water droplets are spherical because of the surface tension of the water. Due to the effects of gravity and air resistance, water droplets are not positively spherical on Earth.

Bacterial cells come in many shapes, and not all of them are spherical. Many asteroids and moons smaller than 300 km in diameter are irregularly shaped, such as the two moons of Mars. <>

Even though the Earth was formed in an irregular shape in the early days, over time the difference in height flattened out with the flow of the earth's crust, and eventually the difference was less than 26 kilometers from place to place, making the stars appear spherical. However, it should be mentioned that the planet is not only solid matter, but solids, liquids, gases, and plasma coexist; For example, the surface of the Earth has mountains, seas and atmospheres, the surface of Jupiter is dominated by gaseous and liquid matter, and the surface of the Sun is plasma gas and fluid shell. All things considered, the shape of the star is not a perfect sphere, but it doesn't seem to change much.

In addition, the rotation of the star, the gravitational pull of the companion star, the impact with the asteroid, and the movement of the earth's crust also affect its shape, but the main factor is the interaction between gravity and electromagnetic force mentioned above. At present, the average radius of the earth's crust at the poles and the equator is about 20 km apart. The earth itself is also uneven, but the highest area above sea level is only 9 km, and the deepest trench is only 11 km, which is nothing compared to the radius of the earth of 6,400 km, so the earth is spherical from a distance. <>

The principle is relatively simple, it is the interaction of forces: gravitational force is indeed an important factor, but a slap cannot be slapped, and the electromagnetic force is equally important. The extrusion, stretching, expansion, etc., between substances composed of molecules or ions, are mostly dominated by electromagnetic forces and gravitational forces in different forms.

In the case of the Earth, suppose there is a cube protrusion as high as h on the Earth (in the case of quartz rock): where the ground meets this protrusion, the force experienced is mainly the pressure caused by the Earth's gravity and the repulsion between the rocks, and this h is theoretically so high when they are just in equilibrium: (Note:

Some parameters are different for different shapes; Some parameters are different for different molecule types; The g in the formula is the acceleration due to gravity, and the g is not the same for each planet) 26 km! If the protrusion is not a cube but another shape, the basic principle of its action will not change, but the value of h will change slightly. <>

In the case of the same volume, the sphere is the shape with the smallest surface area, if the water is a cube in space, the corners will be unevenly stressed, and the equilibrium between the molecules cannot be reached, and the attraction force of the molecules of the air in space to the surface water molecules is less than the inside.

Therefore, the net force of water molecules does not mean that the surface of zero-taste water has a tendency to shrink automatically, just as the water spelled out by the system is a sphere that is encased.

Objects always naturally tend to a state of low energy, because this state of low energy is the most stable, and the sphere is such a very stable state, the sphere is completely symmetrical, the force is uniform, the surface under the same volume is the smallest, compared with other shapes, the sphere only needs lower internal energy to maintain its own structure.

Therefore, many other shapes in nature will tend to evolve into more stable spheres, for example, the energy of water molecules on the surface of water droplets is higher than that of water molecules inside water droplets, and in the case that other factors can be ignored, water droplets will tend to form a sphere with the smallest surface area in the hand no more than 30, so as to achieve a lower and more stable state of energy.

Because the surface tension of water tends to minimize the surface area of water, a spherical shape is the shape with the smallest surface area for the same volume, so any liquid with surface tension will appear spherical in weightlessness.

There is no earthly attraction. In the absence of air and weightlessness, the water droplets solidify together and form a spherical shape.

There is a property of the liquid surface called surface tension, which is the mutual attraction between the parts of the liquid surface, so that a circular shape is formed.

The molecules on the surface of the droplet are attracted by the molecules inside, and all of them have a tendency to move inward, resulting in a state of "tension" between any two parts of the liquid surface, which makes the surface of the water droplets have a tendency to shrink. For an object of a certain volume, the surface area of a sphere is minimal. As a result, the molecules of the water droplets always try to move closer together to shrink the surface area so that they become round, or spherical.

Categories: Education, Science, >> Science & Technology.

Analysis: Water droplets are not necessarily round.

1 Droplets of water suspended in the air (like droplets of water in a fog) are round; This is due to the force of attraction between water molecules, the surface tension of water, and atmospheric pressure. The force exerted by the atmospheric pressure on the object is equal on all sides, thus keeping the water droplets round.

2 Falling water droplets, because they are blocked by air molecules, are not necessarily round. Anyone who has seen high-speed photography should know that water droplets are semi-irregular, semi-regular shapes. Semi-irregular is a sharp edge because it is not necessarily bead-shaped, and semi-regular is because it will not have a water chestnut or a right angle, only a smooth angle.

This characteristic is caused by the force of attraction and surface tension between the water molecules.

3 The shape of the water in a vacuum, as we can see on television, is not necessarily round, it is determined by the force of attraction and the surface tension between the water molecules, and it is devoid of the equal effect of atmospheric pressure.

My statement: The study of science should be carried out with rigor, and I am writing the following notes for the benefit of the public.

1.The effect of gravity on every molecule of an object is not equal.

2.The planets in the universe are all round, so the water droplets are also round. Hehe, so any object on the earth is round.

The planet is large enough to produce an intrinsic gravitational force, and there are no external forces in space (there are exceptions), so they form a circle. Small pieces of objects in the universe, such as cosmic dust, debris, and meteorites, are irregularly shaped. Compared to the volume of the planet and the water droplets, it is simply a world apart!

3.Some people say that "gravity" has nothing to do with the fact that water droplets are spheres, but later it is mentioned that the center of gravity is something that is directly related to gravity. The water molecule will slowly not be right, it's actually a moment, otherwise we would have been able to see the process with our naked eye.

4.The circle occupies the smallest volume and the least resistance when falling Why is it just for falling? Isn't it spherical when suspended?

Why just to reduce resistance? Could it be that the water droplets know this and adjust their shape? That sentence is a consequence, not a cause.

5.n How can multiple circles close together be square? It should be said that more than n, not n more than .

If not a liquid, but a solid, multiple spheres can come together to form a variety of shapes, which may be cubic or spherical from a distance, depending on molecular suction, gravity, atmospheric pressure, and other external forces. If it is liquid, the explanation is as above.

This is the same reason why the water droplets on the lotus leaf are spherical and the planets in space are spherical.

All aggregated fluids have a tendency to maintain their minimum surface area without being affected by external forces. In the case of a certain volume, the surface area of the spherical shape is the smallest, so the fluid that is gathered into a clump will remain spherical. A spherical shape is also called a "hydrostatic equilibrium state".

It's just that the water droplets remain spherical in shape, relying on their surface tension. The planet remains spherical in shape because of its internal gravitational pull. But the result is the same.

Human science and technology are constantly advancing, from many things that could not be explained in the past, to now they have successfully entered spaceAt this time, I really realized that the earth we live on is just such a small and ordinary existence, and then I will find out why all the planets are spherical? In fact, this is because to ensure the stability of the planet, the spherical shape is the best, and at the same time, there is a great gravitational force and other relationships.

Gravitational action. Because all planets use gravitational attraction to make the matter on the planet as close to the center of the sphere as possible, the planets are spherical.

Gravitational action. Planets are gravitational, and gravity is the force in all directions of 360 degrees, so it forms a spherical shape.

The celestial bodies of the universe not only have gravitational and repulsive forces against each other, but in the early days, there were stars everywhere in all directions, repelling and squeezing each other, causing all the planets to be spherical.

Why are all planets spherical?

Why are the planets spherical?

Why are all planets spherical?

Stellar: The most typical is the Sun, where the maximum temperature on the surface of the star can reach 40,000 to 70,000, and the lowest is also in the thousands of degrees Celsius. In this case, there is no solid, liquid matter on the star, but some gaseous state.

The gas diffusion is the same in all directions, and the range is roughly equal, and the gas in all parts is controlled by gravity. So when these forces are balanced, it has a spherical appearance, which is one reason why the stars we look like are round.

Planet: It does not emit light per se, it is not a star in a gaseous state, but a hard solid sphere. But when it was just taking shape, it was also a red-hot molten substance.

Because it has a rotation, it changes its shape to be spherical or oblate. The spherical shape thus formed is mechanically called a "rotating sphere", or "rotating ellipsoid". The moons of the Moon and some other planets are also round and oblate in shape.

Of course, in the universe, in addition to stars and planets, there are also some nebulae, asteroids, moons and other celestial bodies, these celestial bodies are not spherical, but show an irregular shape, but because the number of these celestial bodies is not large, most of our planets are round.

Why are the planets spherical?

Why are all planets spherical?

Look at why the earth is round, and you will know why most of the celestial bodies in the universe are round.

Not only is the Earth round, but most of the celestial bodies in the universe are round. Have you ever seen the round water droplets on the lotus leaves? Liquid matter must shrink into a spherical shape under its own gravitational force, which is the most basic physical law in the universe, and only by shrinking into a spherical shape can the balance of gravity inside the object be achieved.

In other words, when the gravitational force inside the object is balanced, it will inevitably become spherical. Because the spherical shape is the most perfect and stable. That's what perfection means.

For example, on a microgravity space station, water flows out and automatically shrinks into a spherical shape. The Earth was also a hot liquid planet in its early days, so it naturally contracted into a spherical shape under its own gravitational pull. Even when a celestial body is large enough, even if it is made of solid matter, it will gradually collapse into a spherical object under its own gravitational or gravitational pull.

Therefore, most of the large celestial bodies in the universe are spheroids!

Why are the planets spherical?