Our topic for today is Magnetic Field. The region surrounding a magnet in which the force of the magnet can be experienced is called its magnetic field. To view a magnetic field take a bar magnet and keep it on a table. Keep a transparent sheet on the top of the magnet. Now, take some iron filings and sprinkle them on the paper. In reality, the iron filings will arrange immediately after getting sprinkled. The iron filings will start arranging in a definite pattern around the magnet. This pattern is called a magnetic field. The lines along which the iron filings arrange are called magnetic field lines. The magnetic field lines show the direction and strength of the magnetic field. Magnetic field lines always start from the north pole of the magnet and end at the south pole. Inside the magnet, their direction is from the south pole to the north pole. Thus, the field lines form closed loops. Field lines never cross or intersect each other. The closeness of the magnetic field lines tells us about the strength of the magnetic field in that area. The more closely packed lines indicate stronger magnetic field. Therefore, we can see more iron filings sticking at the poles. As the lines spread out, the magnetic field weakens.