"Safe Use of Electricity" PPT download

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"Safe Use of Electricity" PPT download

Part 1: Electric shock and the risk of electric shock.

The human body is a conductor. When voltage is applied to the human body, current will flow through the human body. When the current passing through the human body is very small, people will not feel it; when the current passing through the human body is slightly larger, people will feel "numb and electricity".

When the current reaches a certain value, it is difficult for people to get rid of the voltage, resulting in dangerous electric shock accidents. When the current reaches 100mA, people will suffocate or even die in a very short time.

Example of electric shock: video of little mouse being electrocuted

1. The greater the current passing through the human body, the shorter the time from electric shock to death.

Question 2: When two hands touched the positive and negative terminals of a dry battery, why did no electric shock accident occur?

Question 3: According to Ohm's law, what does the current in a conductor depend on? What determines the size of the current passing through the human body?

2. The size of the current passing through the human body is determined by: the external voltage and the human body's own resistance.

Question 4: Do different people have the same resistance? Is the resistance the same for the same person at different times?

Question 5: So, what is the safe voltage value for the human body?

PPT on the safe use of electricity, part 2: several types of electric shock.

1 Electric shock in household circuits.

People come into contact with the live wire and the neutral wire or the live wire and the earth.

in conclusion

In household circuits, electric shock is usually caused by direct or indirect contact with _______.

2 High voltage electric shock.

3 Other electric shocks.

PPT on the safe use of electricity, part three: measures after an electric shock accident

Which of the following measures is more effective when an electric shock is discovered? ( )

A． Use a wet wooden stick to open the wires.

B. Quickly pull the switch to cut off the power.

C. Use your hands to pull the person who received an electric shock directly away from the power source.

D. Seek medical attention.

Wooden sticks are insulators, but water containing impurities is a conductor. Rescue with wet wooden sticks will not only fail to save people, but will also cause electric shock to the rescuers. Seeking medical personnel will delay the opportunity to rescue people. It is better to cut off the power first. The human body is Conductors, if you directly pull the electric shock victim away from the power supply with your hands, it will cause an electric shock accident to the rescue personnel. The best way is to pull down the switch and cut off the power supply.

Answer B

If a fire breaks out due to a short circuit in a wire, can you use water to extinguish the fire immediately? Why?

Answer: No, because impure water can conduct electricity and will aggravate the disaster. The power supply must be cut off quickly and the fire must be extinguished with sand and fire extinguishers.

PPT on safe use of electricity, Part 4: Principles of safe use of electricity

Do not come into contact with low-voltage charged objects and do not approach high-voltage charged objects.

Before replacing the fuse, be sure to pull down the switch to avoid human body contact with live wires.

Keywords: Zhejiang Education Edition eighth grade science PPT courseware for the second volume free download, safe use of electricity PPT download, .PPT format;

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"Safe Use of Electricity" PPT courseware:

"Safe Use of Electricity" PPT courseware Part One: Review before class There are two wires in the home circuit, one is called ______ wire and the other is called ______ wire. There is a voltage of ______ volts between the live wire and the neutral wire, and a voltage of ______ between the neutral wire and ground. Low voltage power supply line..

"Safe Use of Electricity" PPT:

"Safe Use of Electricity" PPT Part One Content: Classroom Experience Experience: Connect the positive and negative terminals of two dry batteries with your hands, experience it and talk about your feelings. Analyzing the data in the table, it can be concluded that the current passing through the human body _______, and the degree of harm caused is also _______. Notice..

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Update Time: 2024-10-01

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