"Archimedes' Principle" Buoyancy PPT Courseware 3

Description

"Archimedes' Principle" Buoyancy PPT Courseware 3

Archimedes (Archimedes, 287 BC ~ 212 BC) was a great scientist in ancient Greece. There are two main contributions he made in physics: one is about the problem of buoyancy; the second is about the problem of lever balance.

Archimedes (approximately 287-212 BC) was an ancient Greek physicist, mathematician, and the founder of statics and hydrostatics.

The king asked the goldsmith to make a new crown of pure gold. But he suspected that the goldsmith had adulterated the crown. However, there is no problem with the finished crown in terms of weight and appearance. The king gave this problem to Archimedes. Archimedes thought day and night. One day, he went to the bathhouse to take a bath. When he slowly sat in the bathhouse, the water overflowed from the edge of the basin. He looked at the overflowing water and suddenly shouted: "I know!" and ran home naked. . It turns out he figured out a way. Archimedes put the golden crown into a jar filled with water, and some of the water overflowed. He took the crown, filled it with water, and put a piece of gold as heavy as the crown into the water, and some water overflowed. He compared the water from the two times and found that more water overflowed in the first time than in the second time. So he concluded that the gold crown was mixed with silver. After some experiments, he calculated the weight of the silver. When he announced his discovery, the goldsmith was stunned. The significance of this trial was far greater than finding out that the goldsmith had deceived the king. Archimedes discovered a principle: the weight of an object reduced in a liquid is equal to the weight of the liquid he displaced. This principle was later named after Archimedes.

Do you have an answer?

A liquid or gas exerts a vertical upward force on an object immersed in it. In physics, this force is called buoyancy.

Direction of buoyancy: vertically upward.

The cause of buoyancy: an object immersed in a liquid is subject to the difference between the pressure on the lower surface of the object and the pressure on the upper surface of the object.

F float = F lower surface - F upper surface

Experimental phenomena:

⑴. In clear water, eggs sink.

⑵ After adding salt to the clear water, the density of the salt water increases, and the eggs slowly float up until they are in a floating state.

Experimental conclusion: Conjecture 1 is correct. The buoyancy force is related to the density of the liquid.

Conjecture 2: Buoyancy may be related to the volume of the object

Observation experiment:

⒈Immerse the same object into the same liquid at different depths.

⒉Are the readings of the two spring dynamometers the same? What are the differences?

⒊What changes occur to the liquid level in the container?

⒋What problem did the experiment illustrate?

experiment analysis:

① If the same object is immersed in the same liquid, but the volume immersed in the liquid is different, the readings of the spring dynamometer will also be different.

②. The liquid level of the liquid increases as the volume of the object immersed in the liquid increases.

③. The volume immersed in a liquid is also called the volume of the liquid displaced by the object.

Experimental results:

In Conjecture 2, the size of the buoyancy force is related to the volume of liquid displaced by the object.

design experiment:

⑴Put the object into clean water and observe the reading F1 of the force gauge.

⑵Change the depth of the object in the water, and then observe the reading F2 of the force gauge.

⑶ Compare the two readings F1 and F2.

Content of Archimedes' Principle: When an object is fully or partially immersed in a liquid, it will experience an upward buoyant force equal to the gravity of the object displacing the liquid.

Mathematical expression of Archimedes' principle:

F float = G discharge liquid F float = liquid gv discharge

A. When the volume of liquid displaced by an object is equal, the greater the density of the liquid, the greater the buoyancy force.

B. When the density of liquids is equal, the larger the volume of liquid displaced by an object, the greater the buoyancy force.

Application of Archimedes' Principle

1. A ship is a floating body. F float = G object.

2. Submarines sink and float by changing their own gravity.

3. Density meter: measure the density of liquid, the scale is small at the top and large at the bottom.

4. Balloons and airboats achieve lift by changing the volume of objects immersed in the air to change the buoyancy force received.

1. Weighing difference method

1). Use a spring dynamometer to weigh the weight G in the air.

2). Then weigh the tensile force F of the spring scale when the object is immersed in the liquid.

The buoyant force on the object is Fbuoyancy = G – F bomb.

2. Pressure difference method

F float = F up - F down

illustrate:

a. An object F floating on the liquid surface floats = F upward

b. An object that is completely in contact with the bottom floats F = 0

A density meter is an instrument used to measure the density of liquids. The buoyancy force experienced by the density meter in different liquids is the same, which is equal to its own gravity (working principle of the density meter). Therefore, the volume of liquid displaced in a liquid with a high density is small, so The scale of the density meter is small at the top and large at the bottom.

①. The scale value on the density meter is the ratio of the density of liquid to the density of water, so the final measurement result is the scale value multiplied by the density of water.

②. The role of small lead shot encapsulated in the glass bubble at the lower part of the density meter is to lower the center of gravity of the density meter and improve the stability of the density meter in the liquid.

The floating and sinking conditions of objects

(1) Floating and sinking conditions: The floating and sinking of objects immersed in liquid depends on the size relationship between ________ and ________.

①When F floating > G object, the object ________.

②When ___________, the object is suspended.

③When F floating < G object, the object ________.

(2) Floating conditions: ________ (at this time, part of the object is exposed to the liquid surface)

(3) Application of floating and sinking conditions

① Density meter: It is made based on the principle of _______________. The buoyancy force on the density meter is equal in all liquids.

②Ship: Ships are in _________ state in different waters, but ___________ are different. The load capacity is the displacement.

③Submarine: It achieves the purpose of floating and sinking by changing ___________.

④Hot air balloon: The gas volume in the balloon changes (i.e. the volume of displaced air) and changes the ____________ to achieve the purpose of floating up and down.

[Reminder Points] When comparing the relationship between F float and G object to judge whether an object floats or sinks, F float refers to the buoyancy of the object immersed in the liquid. "Floating" and "suspended" are two different states. "Immersed in" and "immersed in", the former includes the latter.

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

For more information about the PPT courseware "Archimedes' Principle of Buoyancy", please click the Buoyancy ppt Archimedes Principle ppt tag.

"Archimedes' Principle" Buoyancy and Lift PPT courseware:

"Archimedes' Principle" Buoyancy and Lift PPT courseware teaching objectives 1. Know Archimedes' Principle through experimental exploration; 2. Be able to use Archimedes' Principle to solve problems related to buoyancy. Teaching focus: Archimedes' Principle thinking activation A wooden block is placed on a level surface...

"Archimedes' Principle" Buoyancy PPT Courseware 8:

"Archimedes' Principle" Buoyancy PPT Courseware 8 1. Review 1: What is buoyancy? Design experiment: As shown in the figure, use a spring dynamometer, a block, a thin wire, a beaker, water and other equipment to compare the readings of the spring dynamometer when the block is in air and water. Steps: (1) In...

"Archimedes' Principle" Buoyancy PPT Courseware 7:

"Archimedes' Principle" Buoyancy PPT Courseware 7 Archimedes' Inspiration More than two thousand years ago, the Greek scholar Archimedes wanted to measure the volume of a gold crown in order to identify whether it was pure gold. He thought hard for a long time but failed. result. One day, he stepped into a bathtub filled with water...

File Info

Update Time: 2024-11-20

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

Preview