• Magnetic fields

This is an activity.

Write an introduction to what the reader will be looking at, assume they know physics but didn't do the activity.
Write some background on magnetic fields and how to see how strong the field is.

Objective; Observe and sketch the magnetic fields around several magnetic configurations.

Materials:

• Two bar magnets
• One horseshoe magnet
• Soft iron 10 penny nail
• Aluminum bar
• Shaker of iron filings
• Bar magnet holder
• Compass
• Three sheets of paper

Part A: Bar magnet

1. Bar magnet
   1. Sketch Iron filings pattern
   2. N - N facing, place 2 cm apart facing each other, filings pattern
   3. N - S facing, place 2 cm apart facing each other, filings pattern
   4. N - S facing each other with soft iron between and in contact with them, filings pattern
2. Compass pattern around the magnet.
   1. Arrange 12 "penny" compasses on a sheet of paper.
   2. Slowly lower a bar magnet down into the center of the magnets.
   3. Look for a pattern in the directions that the compass point.
   4. Sketch the compass pattern, using an arrow to show direction of the colored (red?) tip of the compass.
   5. Discuss the compass N-S orientation.
3. Combine the Filings and compass sketch to form the magnetic field lines sketch.

Part B: Broken magnet

1. Two sketches of a broken bar magnet (see the teacher, please don't make your own lab materials!),
   1. broken parts in contact with each other.
   2. broken parts of magnet separated by 2 cm.
   3. Comment on what happens when a magnet is broken based on the field.

Part C: Horse shoe magnet

1. Horse shoe magnet
   1. Sketch Iron filings pattern
   2. Sketch the compass pattern around the magnet(s),
   3. Combine the Filings and compass sketch to form the magnetic field lines sketch

Part D: Metals; Soft iron, Aluminum in a magnetic field

1. Sketch the magnetic field around a piece of soft iron.(Use a keeper or nail)
2. Using the same piece of soft iron, place it in contact with a bar magnet and sketch the field around it now.
3. Sketch the magnetic field around the aluminum bar.
4. Using the same aluminum bar, place it in contact with a bar magnet and sketch the field around it now.

Observations for each sketch. Observations must be in sentence form.

Questions;

1. When one breaks a magnet what is the magnetic result?
2. The "keepers" are made of soft iron. Are they magnets, magnetic or have no magnetic effect.
3. Are all metals magnetic? Support your answer with observations from this activity.