"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 3

Description

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 3

Situation introduction

Are magnetism and electricity related?

magnet charged body

Can attract magnetic substances and attract light and small objects

There are North and South poles and there are positive and negative charges.

Magnetic poles with the same name repel each other. Same charges repel each other.

Magnetic poles with different names attract each other. Charges with different names attract each other.

1. Magnetic effect of electric current

Demonstration: Magnetic Effects of Electric Current (Oersted Experiment)

1. Place the wire above the small magnetic needle so that it is parallel to the small magnetic needle.

2. Turn on the power (short circuit) and observe whether the small magnetic needle rotates and the direction of rotation.

3. Repeat the above experiment by changing the direction of the current, and then observe the rotation direction of the small magnetic needle. When the direction of the current changes, does the small magnetic needle rotate in the same direction?

Since electricity creates magnetism, why can't a flashlight even attract a pin when it's powered on?

This is because the magnetic field is too weak. If the wires are wound around a cylinder, a solenoid (coil) is made. The magnetic fields generated by each wire are superimposed, and the magnetic field will be much stronger.

2. Magnetic field of energized solenoid

1. Wrap a wire around a cylinder to make a solenoid (also called a coil). After energization, the magnetic fields of each circle of wires are superimposed and the magnetic field is enhanced.

1. Place the small magnetic needle at different positions of the solenoid (starting from both ends) and note the direction of the north pole when the small magnetic needle is stationary, which is the direction of the magnetic field at that point.

2. Change the direction of the current and redo the above experiment to see if the magnetic field in the energized solenoid changes when the direction of the current changes.

3. Use iron powder to demonstrate the magnetic field of an energized solenoid. (Be sure to spread iron powder evenly on the glass plate)

think about it

When the direction of electricity is changed, what is the difference in the direction of the small magnetic needle? What does it mean?

The small magnetic needle points in the opposite direction, indicating that the polarity of the two ends of the energized solenoid is related to the energized current.

3. Ampere’s rule - right-hand spiral rule

Determination of solenoid polarity:

Hold the solenoid in your right hand,

The four fingers rotate with the current,

The thumb points to the N pole.

Knowledge sorting

in conclusion:

1. Like a magnet, a current-carrying conductor also has a magnetic field around it.

The direction of the magnetic field is related to the direction of the current.

2. There are ______ around the energized solenoid,

The distribution of magnetic field lines around an energized solenoid is very similar to that of _________.

The polarity of the energized solenoid is related to __________,

The relationship between them can be determined by __________.

Practice in class

1. Determine the N pole and S pole in the solenoid below:

2. Determine the direction of current in the solenoid:

3. Mark the N and S poles of the energized solenoid in the diagram below.

4. The picture below shows two light and small energized solenoids. When they are close to each other, they will ( )

A.Stay still B.Attract each other

C. mutually exclusive D. move left together

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For more information about the PPT courseware "From Compass to Maglev Train Current's Magnetic Field", please click the From Compass to Maglev Train's ppt Current's Magnetic Field ppt tag.

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 4:

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 4

New knowledge exploration

1. Electromagnet

Definition: An energized solenoid inserted into an iron core is called an electromagnet.

Working principle: Use the magnetic effect of electric current to work.

So the magnetic size of the electromagnet is related to...

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 2:

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware 2

Review: What is observed when a small magnetic needle is placed around a bar magnet? What is the reason?

The small magnetic needle is observed to deflect.

Reason: Because there are magnetic fields around the magnet...

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware:

"Magnetic Field of Current" From Compass to Maglev Train PPT Courseware

1. Oersted’s experiment

1. Place a wire parallel to the small magnetic needle. When the circuit wire is connected, the current passes through the small magnetic needle. When the circuit wire is disconnected, the current passes through the small magnetic needle.

File Info

Update Time: 2024-10-07

This template belongs to Physics courseware Shanghai Science Edition Ninth Grade Physics industry PPT template

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