"Charge Triboelectricity" Current and Circuit PPT Courseware 4

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"Charge Triboelectricity" Current and Circuit PPT Courseware 4

electrostatic phenomenon

Observation and Experimentation Triboelectricity

Rub a plastic comb, plastic ruler or plastic pen holder against your hair, then hold it close to scraps of paper and observe the phenomenon.

Phenomenon: Rubbed combs and rulers can attract scraps of paper.

Take a bunch of plastic strapping ropes that have been torn into filaments and smooth them from top to bottom with dry hands. What do you see?

Phenomenon: The binding ropes are scattered outward one by one.

Explanation: Rubbed objects have the property of attracting light and small objects.

If an object has the property of attracting small objects, it is said to be "electric" or charged. Such an object is called a charged body.

The phenomenon that a rubbed object attracts light and small objects is the phenomenon of triboelectricity. Using friction to charge an object is called triboelectricity.

The law of interaction between charges

Does a rubber rod rubbed with fur have the same charge as a glass rod rubbed with silk?

What happens when two rubber rods rubbed with fur or two glass rods rubbed with silk are brought close to each other?

What happens when a rubber rod rubbed with fur and a glass rod rubbed with silk are brought close to each other?

1. There are only two kinds of electric charges in nature.

The charge on the glass rod rubbed with silk is called positive charge

The charge on a rubber rod rubbed by fur is called negative charge

2. Interaction between charges:

Like charges repel each other

Different charges attract

Group discussion: Can you tell whether a rubber rod is electrically charged? Speak your way.

Method 1: Put the rubber rod close to the scraps of paper and see if it can be attracted. If it is attracted, the rubber rod will be charged.

Method 2: Place the rubber rod close to the positively charged and negatively charged objects respectively. If it repels one of them, the rubber rod is charged; if it attracts both, the rubber rod is not charged.

Group discussion: The picture shows the structure diagram of an oxygen atom. Its nucleus carries 8 positive charges, and the electrons outside the nucleus carry 8 negative charges. Is the oxygen atom charged at this time?

Normally, the positive charge carried by the nucleus is equal in quantity to the total negative charge carried by the electrons outside the nucleus, and their electrical properties are opposite, so the atom is neutral, that is, it does not show any electricity to the outside world.

The entire object is uncharged

Group discussion: Based on this material, can you know why a glass rod rubbed with silk is positively charged, and why a rubber rod rubbed with fur is negatively charged?

Atoms are composed of positively charged nuclei and negatively charged electrons. Since the nucleus has a binding force on the electrons, the electrons move around the nucleus. Normally, the positive charge of the nucleus is equal to the negative charge of the electrons outside the nucleus. Atoms are not electrically charged, so the entire object is neutral. The number of positive charges in the nucleus is difficult to change, but electrons outside the nucleus can escape from the shackles of the nucleus and be transferred to another object, thereby changing the number of negative charges carried by the electrons outside the nucleus. Moreover, the atomic nuclei of different substances have different binding forces on electrons.

Application and protection of static electricity

Static electricity phenomena in daily life

1. When friends meet, an electric shock occurs at the moment when both parties shake hands;

2. In the dry season, the sound of discharge is often heard when taking off clothes, accompanied by sparks visible in the dark;

3. When walking in clothes and pants made of chemical fiber fabrics, the clothes and pants will often absorb a layer of dust that cannot be shaken off;

4. When watching TV programs, the viewing effect will be affected by a layer of dust adsorbed on the fluorescent screen.

Protection against static electricity

1. When the tanker truck is driving on the road, the tires are frictionally electrified, and the oil itself is also electrified due to shaking.

Transportation and explosion prevention of dust and powdery materials (cement, flour, etc.)

In the automobile transportation industry, tires can be charged 15 ~ 50 kv at normal vehicle speeds, and transmission belts can be charged 30 ~ 40 kv, up to 80 kv;

In the plastics industry, the surface of plastic products is rubbed

Its potential can reach more than 1 kv, and when celluloid rubs against each other, the charged potential is as high as 40 kv;

In the crushing industry, most powders will become electrified during transportation and processing;

In the electronics industry, due to the miniaturization of products, they are increasingly sensitive to static electricity.

2. Working principle of lightning rod

Most charged clouds have a negative charge at the bottom and a positive charge at the top.

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"Charge Triboelectricity" Current and Circuit PPT Courseware Experience: Triboelectricity Activity 1: Triboelectricity (1) Put a plastic comb (plastic pen, glass rod) close to a small piece of paper. Is the plastic comb (plastic pen, glass rod) attractive? Small pieces of paper? (2) A plastic comb (plastic pen, glass...

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Update Time: 2024-10-03

This template belongs to Physics courseware Lu Jiao Edition Ninth Grade Physics Volume 1 industry PPT template

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