Make a compass
Objective: Students will make a working compass and label the classroom: north, east, south, west.
Audience: All levels.
Materials: bar magnet, needle, piece of cork or Styrofoam, compass, container of water. Note: For early elementary students discuss and experiment with magnetic and non-magnetic items and a magnet. Students can predict out of a collection of items which are magnetic and which non-magnetic. Students can test each item with a magnet and list or place item under category of magnetic or non-magnetic.
Preliminary lesson: Explain that the earth is similar to a giant magnet. Show a picture such as one from Microsoft Encarta(R) 97 Encyclopedia or from a book. Then, place a bar magnet on a table, lay a piece of white copy paper on top of it, sprinkle very fine iron filings over paper and tap paper gently. Compare the magnetic fields of the picture and the one with your magnet.
Procedure: Discuss how sailing navigators need to stay on course to make good time and the different means of finding the directions of north, east, south and west. One way is to use a compass. To make a compass hold a needle in one hand and rub with one end of a bar magnet in one direction only for approximately 20 times. This magnetizes the needle. Stick needle through a cork or piece of Styrofoam. Carefully set in a container of water so that it floats away from the sides. Observe which way it points. Compare to the compass. Label classroom with directions of north, east, south and west.
Assessment: Teacher Observation.
Extension Exercises:
1. See what effect other magnetic objects have on the students homemade compasses by holding an object close to the compass. Question students: How could finding our directions at sea be affected by other objects on our boat that may be near our compass?
2. Magnetize other magnetic objects such as paper clips by rubbing with magnet.
Lesson plan by Terry Hartnett.