"Pressure of Liquids" Pressure PPT courseware

Description

"Pressure of Liquids" Pressure PPT courseware

I believe everyone can do it:

1. Understand the existence of pressure inside the liquid and the direction of the pressure inside the liquid.

2. Understand the factors related to the size of liquid pressure

3. Master the liquid pressure formula and its application

4. Understand the practical application of liquid pressure - connectors, and understand the various connectors in daily life.

Review the past and learn the new

1. What is pressure? What are the effects of stress?

2. What physical quantity does pressure represent? How to define?

doubt

1. Why are the cross-sections of dams narrow at the top and wide at the bottom, trapezoidal in shape?

2. Why do deep-sea fish die after being caught?

3. Why are the deep-sea diving suits worn by divers thicker than shallow-sea diving suits?

in conclusion:

1. Since the liquid is affected by gravity, the liquid exerts pressure on the bottom of the container.

2. Since liquid is fluid, the liquid also exerts pressure on the side wall of the container.

Ask a question: The liquid has pressure on the bottom and side walls of the container. What factors are related to its size? What are the characteristics of liquid pressure?

2. Experimental Research: Factors Affecting the Internal Pressure of Liquids

Ask the question: What are the factors that affect the internal pressure of a liquid?

Conjectures and Assumptions:

Make plans and design experiments:

Conduct experiments and collect data:

Analyze the data and summarize the conclusions:

Exploration experiment 1

Study the characteristics of liquid pressure at different depths underwater.

Experimental steps: Fix the metal box at different depths underwater, without changing the orientation of the rubber membrane, and record the height difference of the liquid level in the U-shaped tube when the rubber is at different depths underwater.

Exploration experiment 2

The relationship between pressure and direction of liquid

There is pressure inside the liquid in all directions;

At the same depth, the pressure of the liquid is equal in all directions.

Exploration experiment 3

Study the relationship between the internal pressure of a liquid and its density.

Experimental steps: Keep the depth of the metal box in the liquid constant, put the metal box into three liquids (salt water, water and alcohol), record the height difference of the U-shaped tube, and change the depth twice.

Summarize:

There is pressure in all directions inside the liquid; at the same depth, the pressure in all directions is _____. As the depth increases, the pressure of the liquid _____; the pressure of the liquid is also related to the density of the liquid. When the depth is the same, the greater the density of the liquid, pressure_____.

Think about it: What will happen to the pressure of liquids with the same depth and different shapes or bottom areas in the test containers?

1. Why are the cross-sections of dams narrow at the top and wide at the bottom, trapezoidal in shape?

The reason why the dam is narrow at the top and wide at the bottom is that the pressure inside the liquid increases with depth. The bottom of the dam is under strong pressure from water, and the bottom width can withstand the pressure.

2. Why do deep-sea fish die after being caught?

Deep-sea fish such as hairtail have lived in the deep sea for a long time, and their internal organs have adapted to the huge pressure in the deep sea. Once out of the ocean, due to the sudden drop in external pressure, internal organs will burst and cause death.

Formula Derivation

Imagine that there is a water column with a depth h and a cross-section s in a glass container. Try to calculate the pressure generated by this water column, which is the pressure at the water depth h.

The volume of the water column is v=sh

The density of water is ρ

The mass of the water column is m=vρ

The pressure of the water column on its base area is F=mg=ρvg=shρg

The pressure of the water column on its base area is P=F/s=ρshg/s=ρgh

Class exercises:

1. As shown in Figure 13-5, the water in the bottle flows out from small holes A and B, which means that the liquid has pressure on the _____ of the container. The water shot out from hole B sprays faster, which means that the pressure of the liquid increases with the pressure of the container. Increases as _____ increases.

2. As shown in Figure 13-6, a container contains a certain amount of water and is placed stationary on an incline. The relationship between the pressures PA, PB, and PC at points A, B, and C at the bottom of the container is: _____.

3. The following table is some of the data measured by Xiao Ming using the experimental device shown in the picture to explore liquid pressure:

(1) One set of data obtained from the experiment is wrong, and its experiment number is __________.

(2) Comprehensive analysis of the above experimental data, the rules of liquid pressure can be summarized: a. ＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿． b.＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿＿．

4. There is a certain amount of water in the test tube as shown in the figure. When the test tube is placed vertically, the pressure of the water on the bottom of the tube is p1; when the tube is placed tilted, the pressure of the water on the bottom of the tube is p2. Compare p1 and p2. size, then ()

A. p1>p2B． p1

C. p1=p2D． Insufficient conditions to judge

Application of connector----Ship lock

Open the upstream valve A, and the lock chamber and the upstream water channel form a connector.

After the water level in the lock chamber rises to be equal to the water level upstream, the upstream gate is opened and the ship sails into the lock chamber.

Open the downstream valve B. The lock chamber and the downstream water channel form a connector.

After the water level in the lock chamber drops to the same level as the water level downstream, the downstream gate is opened and the ship sails downstream.

1. As shown in the figure, the pressure relationship between two points A and B is ( )

A.PA=PB B.PA>PB C.PA

2. Insert the glass tube with a rubber film on one end into the water, as shown in the picture. During the gradual insertion process, the rubber film will [ ]

A. Gradually convex downward. B. Gradually convex.

C. constant. D. Hard to judge.

3. 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 will be ( )

A. Get bigger B. become smaller

C. UnchangedD. Unable to judge

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For more information about the "Pressure of Liquids" PPT courseware, please click on the "Pressure PPT of Liquids" PPT tab.

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Update Time: 2024-06-30

This template belongs to Physics courseware People's Education Edition Physics for Grade 8, Volume 2 industry PPT template

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