"Studying the Pressure of Liquids" Magical Pressure PPT Courseware 2

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"Studying the Pressure of Liquids" Magical Pressure PPT Courseware 2

1. Surprising experiment

Activity 1 Watch the experiment imitating Pascal

2. Explore the characteristics of internal pressure of liquids

The liquid not only exerts pressure on the bottom of the container, but also exerts pressure on the side walls of the container.

The reason why liquid generates pressure: Due to the fluidity of liquid and the effect of gravity,

The liquid exerts pressure on the bottom and side walls of the container. Does the liquid also have pressure inside?

In order to further reveal the characteristics of liquid pressure, it is necessary to use a pressure gauge to study it. So, let’s first get to know the U-tube pressure gauge.

2. Explore the pressure inside the liquid

Watch the internal pressure experiment of liquids

(1) There is pressure in all directions inside the liquid, and the pressure is the same in all directions at the same depth

(2) The pressure inside the liquid is related to the depth. The greater the depth, the greater the pressure;

(3) The internal pressure of different liquids is related to the density of the liquid. The greater the density, the greater the pressure.

The internal pressure of a liquid depends on the density and depth of the liquid, and has nothing to do with the mass of the liquid (gravity or quantity), the bottom area of ​​the container, the shape of the container, etc.

practise

1. Compare the pressures at points a, b, and c in the following figures.

2. If the cup is filled with water and you immerse your hand in the water, the pressure of the water on the bottom of the cup ( )

A. Get bigger b. become smaller

C. unchanged D. Unable to judge

3. As shown in the figure, there is some water in the test tube. When the test tube is tilted, the pressure generated by the water at the bottom of the test tube will be:

A. Get bigger b. become smaller c. unchanged D． Can't compare

4. Two containers A and B have different cross-sectional areas and both contain water. The water depth and the positions of the four points a, b, c, and d are as shown in the figure. The pressure generated by the water at a, b, c, and d are Pa, Pb, Pc, and Pd respectively. Which of the following relationships is correct ( )

A. Pa < Pc B. Pa = Pd C. Pb > Pc D. Pb=Pd

Analyze and calculate the pressure inside a liquid

Liquid column volume: v=sh

Liquid column mass: m=ρv=ρsh

Liquid column weight: G=mg=ρgsh

The pressure of the liquid column on its bottom surface

F=G=mg=ρgsh

The pressure of a liquid on its bottom surface

P=F/s=ρgsh/s

Liquid pressure formula P=ρgh

Friendly reminder:

1. From p=ρgh, it can be seen that the pressure inside the liquid is only related to the density and depth of the liquid, and has nothing to do with the weight of the liquid, the shape of the container, etc.

2. The h in the formula p=ρgh refers to the vertical distance from somewhere in the liquid to the liquid surface, that is, the depth. (The surface of a liquid in contact with air is called the liquid surface)

3. When p=ρgh is used to calculate pressure, SI units must be used uniformly.

4. p=ρgh is only suitable for finding the pressure of uniform liquids

3. Connector

Definition: A container with an open top and a connected bottom is called a connector

Properties: The liquid level of the same liquid at rest in the connector and in contact with the air is always level.

For example: teapot; watering kettle; culvert; boiler water level gauge; ship lock; cow drinking fountain.

Typical question types:

The relationship between the pressure of liquid on the bottom of the container and gravity in irregular containers

The containers in the following figures are all filled with water. The bottom area of ​​each container is S and the depth of the water is h. Compare the pressure of the water on the bottom of each container and the gravity of the water.

As shown in the figure, the bucket contains water with a weight of 400N. The water depth is 0.6 meters. The bottom area of ​​the bucket is 0.1m2. The mass of the bucket is 5kg (regardless of atmospheric pressure). Find: (g is 10N/kg)

(1) The pressure and pressure of water on the bottom of the barrel.

(2) The pressure and pressure of the barrel on the ground.

Summarize:

Because the liquid pressure is not necessarily equal to the liquid gravity, to calculate the liquid pressure, you usually need to calculate p=ρgh first, and then F= pS

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For more information about the PPT courseware "Magical Pressure to Study the Pressure of Liquids", please click on the Magical Pressure ppt to Study the Pressure of Liquids ppt tag.

"Studying the Pressure of Liquids" Magical Pressure PPT Courseware:

"Studying the Pressure of Liquids" Magical Pressure PPT Courseware Teaching Objectives 1. Know the causes of liquid pressure 2. Know the characteristics of liquid pressure 3. Be able to use the liquid pressure formula to calculate liquid pressure 4. Know what a connector is and what a connector has Feature detection..

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Update Time: 2024-10-03

This template belongs to Physics courseware Guangdong and Shanghai version of eighth grade physics volume 2 industry PPT template

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