LAB – Introduction to Magnetic Fields   A magnetic field is a kind of shield that surrounds magnets. Although it can’t be seen directly, the overall shape can be seen by the effect it has on iron filings. Purpose: In this activity, you will explore the patterns of magnetic fields around the bar magnets in various set-ups. You will also compare the field lines produced with iron filings to those produced using a compass about a single bar magnet. Materials: (1) Bar magnets (2) (2)Iron filings (3) Sheet of white paper Procedure: (A) Place a bar magnet on a horizontal surface. Cover the magnet with a sheet of paper, ensuring that the magnet is under the center. Carefully sprinkle iron filings on top of the paper. Jiggle/tap the paper slightly to help the iron filings move their way into the magnetic field pattern. Curl up the paper and carefully pour the iron flings back into the shaker. Sketch the pattern of the magnetic field below-be sure to draw in the poles. (B) Arrange two bar magnets in a line with opposite poles facing each other. Leave about one inch (2.5 cm) between the poles. Use the iron filings to see the magnetic field as before. Jiggle/tap the paper slightly to help the iron filings move their way into the magnetic field pattern. After you finish your sketch, curl up the paper and carefully pour the iron flings back into the shaker.

Sketch the pattern of the magnetic field below-be sure to draw in the poles. (C) Arrange two bar magnets in a line with same poles facing each other. Leave about one inch (2.5 cm) between the poles. Use the iron filings to see the magnetic field as before. Jiggle/tap the paper slightly to help the iron filings move their way into the magnetic field pattern. After you finish your sketch, curl up the paper and carefully pour the iron flings back into the shaker. Sketch the pattern of the magnetic field below-be sure to draw in the poles. (D) Lay the magnets side by side about one inch apart with opposite poles next to each other. Place the paper on the magnets and sprinkle the iron filings on the magnets as you have done in the previous trials. Jiggle/tap the paper slightly to help the iron filings move their way into the magnetic field pattern. After you finish your sketch, curl up the paper and carefully pour the iron flings back into the shaker.

Sketch the pattern of the magnetic field below-be sure to draw in the poles. (E) Lay the magnets side by side about one inch apart with same poles next to each other. Place the paper on the magnets and sprinkle the iron filings on the magnets as you have done in the previous trials. Jiggle/tap the paper slightly to help the iron filings move their way into the magnetic field pattern. After you finish your sketch, curl up the paper and carefully pour the iron flings back into the shaker. Sketch the pattern of the magnetic field below-be sure to draw in the poles.

Conclusion Questions-Answer questions below in complete sentences, except #3. A magnetic field is strongest where it has the most lines of force. Where is the field strongest around the magnet?   2. Do any of the lines of force sketched in any of the 5 drawings cross each other? 3. Draw the magnetic field for the magnets below. N S N S