"Electromagnets and Their Applications" Magnetic Phenomenon PPT Courseware 4

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"Electromagnets and Their Applications" Magnetic Phenomenon PPT Courseware 4

Apply what you learn

1. The scientist who first discovered the magnetic effect of electric current was: _____.

2. Oersted’s experimental explanation: There is a magnetic field around a current-carrying conductor, and the direction of the magnetic field is related to the direction of the current.

3. The distribution of magnetic induction lines of an energized solenoid is very similar to that of a bar magnet.

What is an electromagnet?

1.Definition: An electromagnet is a solenoid with an iron core.

2.Construction:

3. Working principle: magnetic effect of electric current

Smart design

2. Factors affecting the magnetic strength of electromagnets

(1) Conjecture: The strength of the magnet may be related to the size of the current, the number of turns of the coil and the presence or absence of an iron core.

(2) Experimental equipment: power supply, switch, rheostat, wire, ammeter, pin, electromagnet

(3) Design circuit diagram:

(4) Experimental method: Control variable method Conversion method

(5) How to display the strength of magnetism

Experimental exploration:

①The effect of changes in current on the magnetic properties of electromagnets;

②The influence of the presence or absence of iron core on the magnetic properties of electromagnet;

③The change in the number of coil turns affects the magnetic properties of the electromagnet.

What is the relationship between the magnetic strength of an electromagnet and the magnitude of the current?

Invariant: number of coil turns, all have iron cores

Amount of change: the size of the current

Phenomenon: observe how many pins are attracted

What is the relationship between the magnetic strength of an electromagnet and the number of turns in the coil?

Invariant: the size of the current and the iron core inserted

Amount of change: number of coil turns

Phenomenon: Observe how many pins are attracted

What is the relationship between the magnetic strength of an electromagnet and whether it has an iron core?

Invariant: the size of the current and the number of turns of the coil

Amount of change: with or without iron core

Phenomenon: Observe how many pins are attracted

(7) Conclusion:

The factors that affect the magnetic strength of electromagnets are:

1. The size of the current:

Electric current_______, magnetism of electromagnet_______;

2. Number of turns of coil:

The number of turns of the coil _______, the magnetism of the electromagnet _______;

3. Whether there is an iron core:

______________, the magnetic properties of electromagnets are enhanced.

3. Advantages of electromagnets

(1) The magnetism of the electromagnet can be controlled: it is magnetic when the power is on, and non-magnetic when the power is off.

(2) The magnetic strength of the electromagnet can be controlled: the magnetic strength of the electromagnet can be changed by changing the size of the current.

Whether the electromagnet is magnetic or not can be controlled by_______

The magnetic strength of the electromagnet can be controlled by __________________ and the number of turns.

The polarity change of the electromagnet can be achieved by __________________.

1. The difference between electromagnets and ordinary magnets is ( ).

A. The magnitude of the magnetic force can be changed. B. There are no north and south poles. C. The direction cannot be indicated.

2. Which of the following cannot change the magnetic pole of the electromagnet ( ).

A. Change the direction of the current B. Change the direction of the coil winding C. Increase the number of turns of the coil

3. Only change the direction of the electromagnet current, electromagnet ( ).

A. The North and South Pole changes B. The South and North Pole remains unchanged C. The strength of the magnetic force changes

4. Xiao Ming first changes the winding direction of the electromagnet coil, and then changes the current direction of the electromagnet. At this time, the electromagnet is ( ).

A. The North and South Pole changes B. The South and North Pole remains unchanged C. The strength of the magnetic force changes

5. The simplest way to change the north and south poles of the electromagnet in the picture below is ( ).

A. Change the winding direction of the coil B. Change the connection method of the batteries C. Change the number of batteries

Summary

1. The magnetism of electromagnets is related to __________ and _______ and ________.

2. The working principle of electromagnets: using the magnetic effect of electric current.

3. Advantages of electromagnets:

A. The presence or absence of magnetism can be controlled by ______.

B. The strength of the magnet can be controlled by changing the size of ______ and the number of turns of the coil.

C. Its north and south poles can be controlled by changing ______.

4.Application of electromagnet:

Electromagnetic crane electric bell

Telephone receiver Electric toy car

Evaluate exchanges and cooperation

Are your conclusions consistent with your conjecture?

Compare the experimental plan you designed with that of other students. What are the advantages and disadvantages of each? What difficulties did you encounter during your research? How did you overcome it? What research methods did you use? What did you learn?

What other factors may affect the magnetic strength of the electromagnet that were not considered in the above experiment?

Why is the hoof electromagnet more attractive than the bar electromagnet?

Conjectures and Assumptions

1. One of the components that make up an electromagnet is a coil. Will the shape and number of coils affect the strength of the magnet?

2. Another component that makes up the electromagnet is the iron core. Will the presence or absence of the iron core affect the strength of the magnetism?

3. An electromagnet is magnetic only when there is current in the coil, so will the size of the current affect the strength of the magnetism?

Keywords: magnetic phenomena teaching courseware, electromagnets and their applications teaching courseware, Beijing Normal University edition ninth-grade physics PPT courseware download, second volume, ninth-grade physics slide courseware download, magnetic phenomena PPT courseware download, electromagnets and their applications PPT courseware Download, .PPT format;

For more information about the PPT courseware "Magnetic Phenomenon Electromagnet and Its Application", please click the Magnetic Phenomenon PPT Electromagnet and Its Application PPT tab.

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Update Time: 2024-11-18

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