The law of buoyancy was first discovered by Archimedes, an ancient Greek philosopher and mathematician, after observing and calculating the force on objects in water. After the perfection of countless scientists, it is roughly assumed that the fluid is incompressible, and the buoyancy of the fluid to the object in the fluid is perpendicular to the horizontal plane of the fluid in the container, contrary to gravity. The buoyancy is equal to the weight of the fluid displaced by the object.

If the object does not sink to the bottom, then the weight of the fluid discharged by the object is equal to the product of the volume of the object immersed in the fluid and the specific gravity of the fluid, and this product value is the weight of the object!

Suppose the weight of the object is G 1, the volume is v, the volume immersed in the liquid is V2, and the specific gravity of the liquid is p2. Then: buoyancy: F=p2×V2=G 1. This formula can be used to calculate the specific gravity of the liquid in which the object is immersed.

V2=V-V 1, where V 1 is the remaining volume of the object that is not submerged under the fluid surface. If it is a regular cubic object, the measurement is very convenient.

If the specific gravity of an object is p 1, then G 1=p 1×V=p2×V2. This formula is useful in many ways. If you know three quantities, you can find another quantity.

Note that if an object is completely submerged in liquid, its weight is greater than its buoyancy. The above equation does not hold, but the buoyancy is always constant, f = P2× V < G 1. It can be seen that no matter how heavy an object is, the buoyancy it receives is only related to the specific gravity of the fluid and the partial volume submerged in the fluid, and the larger the volume submerged below the surface of the fluid. The greater the buoyancy; More buoyant than mainstream liquid! .

Nothing on the surface of the fluid can be completely submerged in the fluid, and there is always a little submerged below the liquid surface! Otherwise, how can there be buoyancy? .

Cao Chong's image is based on this principle, but unfortunately, the laws of mathematical physics have not been formed, and the rigorous scientific truth has been missed!

He first let the elephant stand on the boat in the water, then carved a mark on the side of the boat, indicating that the boat sank but didn't sink to the bottom. Then he pulled the elephant ashore and put many stones in the boat, so that the boat sank to the side of the boat. Then weigh a large number of stones in the boat separately, and their sum is the weight of the elephant.

The comparison of Chinese and foreign historical facts shows that truth can be found through dialectical thinking on the basis of practice! Be good at contact and comparison, and try to abstract the relationship into quantity! In order to become a strict law of natural science.