Difference Between Pressure of Solids and Liquids

The key difference between pressure of solids and liquids is thatpressure of solids occurs only due to the weight of the solid, whereas pressure of liquid occurs due to both weight and movement of the liquid molecules.

Pressureis a very important concept in physics. The concept of pressure plays a very important role in applications such as热力学空气动力学,fluid mechanics, and deformations. Thus, it is vital to have a good understanding of pressure in order to excel in any field that uses pressure as a base concept.

CONTENTS

1.Overview and Key Difference
2.What is Pressure of Solids
3.What is Pressure of Liquids
4.Side by Side Comparison – Pressure of Solids vs Liquids in Tabular Form
6.概括

What is the Pressure of Solids?

The pressure of a solid arises due to theweight固体。我们可以使用基于液压的参数来解释这种压力。固体内部的原子是静态的。因此，没有固体的动量变化产生压力。但是在某个点上方的实体柱的重量在上述点有效。这会在固体内部产生压力。

但是，由于这种压力，固体不会大量扩展或收缩。固体侧面的压力垂直于重量矢量，总是为零。因此，与液体不同，固体具有自己的形状，它具有容器的形状。

What is the Pressure of Liquids?

To understand the concept of the pressure of liquids, we must first understand the concept of pressure in general. The pressure of a static fluid is equal to the weight of the fluid column above the point of the pressure we measure. Therefore, the pressure of a static (non-flowing) fluid is dependent only on the density of the fluid, the gravitational acceleration, the atmospheric pressure and the height of the liquid above the point the pressure is measured. Also, we can define pressure as the force exerted by the collisions of particles. In this sense, we can calculate pressure using the molecular kinetic theory of gasses and the gas equation. The term “hydro” means water and the term “static” means non-changing. This means hydrostatic pressure is the pressure of the non-flowing water. However, this is also applicable to any fluid, including gasses.

Since hydrostatic pressure is the weight of the fluid column above the measured point we can give it in an equation as P= hdg, where P is the hydrostatic pressure, h is the height of the surface of the fluid form the measured point, d is the density of the fluid and g is the gravitational acceleration.

The total pressure on the measured point is the union of the hydrostatic pressure and the external pressure (i.e. atmospheric pressure) on the fluid surface. The pressure due to a moving fluid varies from that of static fluid. We can use the Bernoulli theorem to calculate the dynamic pressure of non-turbulent incompressible fluids.

What is the Difference Between Pressure of Solids and Liquids?

The key difference between pressure of solids and liquids is that pressure of solids arise only due to the weight of the solid, whereas pressure of liquid arises due to both weight and movement of the liquid molecules. When calculating these pressures, we can calculate the pressure of solids using the weight of solid and the pressure of liquids using both the weight of liquid and movement of liquid molecules. When considering the shapes of solids and liquids, solid has a definite shape because the pressure on the side of the solid, which is perpendicular to the weight vector, is always zero while liquid gets the shape of the container because liquid pressure acts on the sides of the liquid as well as the bottom.

摘要 - 固体与液体的压力

The key difference between pressure of solids and liquids is that pressure of solids arise only due to the weight of the solid, whereas pressure of liquid arises due to both weight and movement of the liquid molecules.

Reference:

1. “Liquid Pressure – Physics Video by Brightstorm.”Brightstorm,Available here.