"Starting from Lightning" Exploring Simple Circuit PPT Courseware 3

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"Starting from Lightning" Exploring Simple Circuit PPT Courseware 3

How is lightning produced?

The movement of clouds will cause friction with the air, and there will also be friction between cloud layers, which will generate and accumulate a large amount of electric charge.

Lightning is the result of electric charges moving from a cloud to the ground or from one cloud to another.

Using friction to charge an object is called triboelectricity.

1. Two kinds of charges

1. Charged objects:

If an object has the property of attracting light and small objects, it means that the object is charged, or charged.

There is often a layer of gray stuck to the fluorescent screen of the TV. This is because when the TV is working, there are _______ on the screen and it has the property of _______.

interaction between charges

Any charged object that repels a glass rod rubbed with silk must be attracted to a rubber rod rubbed with fur.

1. There are only two types of charges in nature

Regulation:

The charge on a glass rod rubbed with silk is called a positive charge;

The charge on a rubber rod rubbed with fur is called a negative charge.

2. Like charges repel each other, and dissimilar charges attract each other.

3. The amount of charge is called charge.

Unit: Coulomb, abbreviation: Coulomb, symbol: C

Two charged bodies with charges of 1 coulomb each are 1 km apart, and the interaction force is about 9 000 N. It can be seen that the Coulomb is a very large unit.

2. Atoms and their structures

1. Common substances are composed of molecules and atoms.

2. Atomic structure

3. Element charge (e): The smallest amount of charge is called element charge

e＝1.6×10-19C

4. Under normal circumstances, the number of positive charges carried by the nucleus is equal to the total number of negative charges carried by all electrons outside the nucleus. The entire atom is neutral, which means that the atom does not appear to be charged to the outside.

Class summary

1. Two kinds of charges

If a rubbed object can attract light and small objects, it means that the object is charged. This phenomenon is called frictional electrification.

1. There are only two kinds of charges in nature: positive charge and negative charge.

2. Interaction between charges

Like charges repel each other and dissimilar charges attract each other

3. Charge amount

The amount of charge is called charge. Unit: Coulomb (C)

4. Electroscope

Function: Check whether the object is charged

Principle: Like charges repel each other

practice

1. The charge generated by triboelectricity has brought a lot of trouble to people in production and life. Among the following phenomena, the ones that are not caused by triboelectricity are ( )

A． In the dry autumn and winter seasons, when you take off your sweater at night, you will find some small sparks, which will cause pain to your skin.

B． Clothes made of chemical fiber fabrics tend to absorb dust

C. When you touch an outdoor iron rod with wet hands in winter, your hand will get stuck to the iron rod.

D. In dry weather, when you comb your hair with a plastic comb, your hair will fly with the comb.

[Analysis] Choose C. When you touch an iron rod outdoors with wet hands in winter, the water freezes when it becomes cold, causing your hand to stick to the iron rod. This is a solidification phenomenon; while the other three phenomena are due to frictional electrification. caused, so choose C.

2. When weaving a certain kind of carpet, some stainless steel wires are mixed in during the weaving process. This is because ()

A. Make the carpet look better

B.Make the carpet more durable

C. Make carpets better at conducting heat

D. Release static electricity to make the carpet less likely to be stained with dust.

[Analysis] Choose D. When people walk and rub against the carpet, it will become charged and attract dust in the air. When weaving the carpet, some stainless steel wires are mixed in. Since the stainless steel wire is a conductor, it can release static electricity, making the carpet less likely to be stained with dust.

3. CCTV’s “Samsung Intelligence Express” program introduced that bees fly and friction with the air generates static electricity, so bees can attract positively charged pollen during flight. The following statement is correct ( )

A. Bees are negatively charged B. Bees are positively charged

C. Air is uncharged D. Air is negatively charged

[Analysis] Choose A. Static electricity is generated by bees and air friction. Then the bees and the air are both charged bodies and have different charges. Bees and positively charged pollen attract each other and attract each other based on different charges, so the bees are negatively charged and the air is. It is positively charged, so choose A.

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"Starting from Lightning" Exploring Simple Circuit PPT Courseware 2:

"Starting from Lightning" Exploring Simple Circuit PPT Courseware 2 Teaching Objectives 1. Understand the phenomenon of frictional electrification. 2. Understand the rules of two kinds of charges and their interaction. 3. Lightning is a discharge phenomenon. Know the application and protection of static electricity. Detection Preview 1 1. Know the starting point of friction..

"Starting from Lightning" explores simple circuit PPT courseware:

"Starting from Lightning" explores simple circuit PPT courseware Learning objectives 1. Understand the phenomenon of frictional electrification. 2. Know the rules of two kinds of charges and their interaction. 3. Know that lightning is an instantaneous large-scale discharge phenomenon. Core test points: Frictional electrification, electric charge..

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Update Time: 2024-08-06

This template belongs to Physics courseware Guangdong and Shanghai Edition Ninth Grade Physics Volume 1 industry PPT template

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