"Buoyancy" PPT courseware 2

Description

"Buoyancy" PPT courseware 2

learning target

1. Understand what buoyancy is through phenomena. The direction of buoyancy and the force exerting force

2. Be able to use a spring dynamometer to measure the buoyancy force.

3. Understand the causes of buoyancy

4. Be able to use the control variable method - to explore the factors related to the size of buoyancy. And can initially judge the size of the buoyancy (difficulty)

2. Self-study questioning:

1. Ducks can float on the water, and ships made of steel can also float on the water, which shows that they are subject to the ____ force of the water on them.

2. Airships and hot air balloons can rise into the sky, which means that they are also subject to the upward ____ force of the air on them.

3. When we lift a stone from water, it feels ____ ("lighter" or "heavier") than lifting it in the air. These examples all show that objects that sink in water are also affected by the ____ force of water. . ………..

4. Understand buoyancy:

From the above buoyancy phenomena, it can be concluded that all objects immersed in liquid or gas are supported by the liquid or gas. This force is called buoyancy. The direction of buoyancy is always ____. The force exerting force on the buoyancy force is ____ (optional "same" or "opposite") as the direction of gravity.

Do you think ":immerse" is the same as "immerse"?

Conclusion: factors that determine the size of buoyancy

There are _________ and _________. The bigger the _________, the bigger the _________, the greater the buoyancy force it will experience. The size of the buoyancy force _________ has nothing to do with _________, the density, shape, etc. of the object.

Application and consolidation:

1. Put two objects A and B with equal volumes into water. Their conditions when they are at rest are as shown in the figure. The correct one of the following statements is ( )

A. The buoyant force on object A is equal to the buoyant force on object B

B． The buoyant force on object A is greater than the buoyant force on object B

C. The buoyant force on object A is less than the buoyant force on object B.

D． It is impossible to tell who is more buoyant

2. The same object is immersed in kerosene and water, and the buoyancy force it experiences is greater in ____.

3. A, B, C, and D are four balls with the same volume and shape but different materials. When they are put into the water and stand still, the situation is shown in the figure below. The buoyancy force among them is: FA__FB__FC__FD.

Summary: What knowledge did you learn in this lesson?

1. Buoyancy: An object immersed in a liquid (or gas) is pushed upward by the liquid (or gas).

Direction: vertically upward; force applying object: liquid or gas

2. Measure buoyancy by weighing method: F float = G-F means

3. The reason for buoyancy is that the upward pressure of the liquid on the object is greater than the downward pressure. This pressure difference is buoyancy.

4. Factors that determine the size of buoyancy: It is related to the volume immersed in the liquid and the density of the liquid. The larger the volume immersed in the liquid, the greater the density of the liquid and the greater the buoyancy force it experiences. It has nothing to do with the depth of immersion, the shape of the object, and the density of the object.

1. An egg is suspended in a container filled with salt water. The container is placed on an inclined surface, as shown in the figure. Several directions of forces are drawn on the picture. You think the direction of the buoyancy force on the egg should be F1, F2, F3 or F4.

2. A metal block weighs 27N in the air. If it is completely immersed in water, the reading on the spring dynamometer is 17N. Then the buoyancy force on the metal block is ____N.

3. After a diver leaves the platform, from the time he touches the water to when he is completely immersed in the water, the buoyancy force he receives will be ; when he is fully immersed in the water and sinks, the buoyancy force he will receive will be .

4. Press the ball into the water. When you let go, the ball will float. Before the ball emerges from the water, the correct change in the pressure and buoyancy of the water is ( )

A. The pressure decreases and the buoyancy remains unchanged.

B. The pressure increases and the buoyancy remains unchanged.

C. The pressure remains unchanged and the buoyancy increases.

D. The pressure remains unchanged and the buoyancy becomes smaller.

Keywords: buoyancy teaching courseware, New People's Education Edition eighth grade physics PPT courseware volume 2, eighth grade physics slide courseware download, buoyancy PPT courseware download, .ppt format

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Update Time: 2024-11-18

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

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