Whether the object sinks or floats in the water09

Whether the object sinks or floats in the water depends on how much buoyancy the object is subjected to in the water, if the buoyancy is greater than the weight of the object, the object floats on the water; If the buoyancy force is less than the weight of the object, the object will sink to the bottom of the water due to gravity.

When the density of the object is greater than the density of the water, the object sinks in the water.

When the density of the object is less than the density of the water, the object floats on the water.

Buoyancy method

Experimental equipment] wooden blocks, water, fine needles, graduated cylinders.

Experimental procedure] 1. Inject an appropriate amount of water into the graduated cylinder, and the readout volume is V1;

2. Put the wooden block into the water, float, and read the volume v2 after being stationary;

3. Insert the wooden block with a fine needle, completely immerse the wooden block in water, and read the volume as V3.

Calculation Expression] = Water (v2-v1) (v3-v1).

Archimedes' law, that is, the buoyancy of an object: if it is greater than the gravitational force it displaces the liquid, it floats; If it is equal to it, it will be suspended; If it is less than, it will sink. To be more specific;

1) It is related to the density of the object, such as the density of iron is greater than that of water, sinking; Wood is less dense than water, floating;

2) It is related to the shape, such as the iron basin floating, the iron block sinking;

3) It is related to volume, such as salt mass sinking, salt molecule floating;

4) It is related to the surface area, such as a piece of paper floating, a stack of paper sinking.

Scope of application

Archimedes' principle applies to objects that are fully or partially immersed in a stationary fluid, requiring that the lower surface of the object must be in contact with the fluid.

If the lower surface of the object is not fully in contact with the fluid, for example, a bridge pier that has been submerged in water, a shipwreck inserted into the seabed, a pile driven into the bottom of a lake, etc., in this case, the force of the water is not equal to the force specified in the principle.

This principle also does not apply if there is a significant flow of water relative to the object (see Bernoulli's equation). The fish swims in the water, and the force calculated by Archimedes' principle is only a partial value due to the disturbance of the surrounding water.

In these cases, the effects of hydrodynamics are taken into account. The lifting force of the hydrofoil is much greater than the buoyancy force, which is a dynamic effect, and the law followed is different from that of statics.

5. Whether the object sinks or floats in the water.

Objects that sink in the water will also be buoyant, and generally the objects sink to the bottom and do not fit the bottom surface, such as sinking stones, which are still buoyant after they sink to the bottom, and they do not float up because the buoyancy is less than their gravity.

The force exerted on an object due to the attraction of the earth is called gravity. The object of gravity is the Earth. The direction of gravity is always straight downwards.

The gravitational force experienced by the object is proportional to the mass of the object, and the calculation formula is: g=mg, g is the proportionality factor, the magnitude is about, the gravitational force changes with the change of latitude, and the gravitational force of an object with a mass of 1kg is. The point at which gravity acts on an object is called the center of gravity.