MAGNETISM AND THE COMPASS

SHORT TERM GOALS:

  1. To help students become familiar with the compass and its importance on travel.
  2. To help students make connections between compass directions and the magnetic field that surrounds the earth.

TIME ALLOTMENT: 1 hour

CONTENT AREAS ADDRESSED:

  1. Science
  2. Geography
  3. Language Arts

CONCEPTS ADDRESSED:

  1. Magnetism
  2. Direction
  3. Travel

MATERIALS:

  1. Paper and Pencil
  2. Needle
  3. Bar Magnet
  4. Small Dish or a Large Cap of Some Sort
  5. Cork

PROCEDURE:

The earth has a thick iron and nickel core, which is constantly convecting. This movement has caused our planet to develop a magnetosphere that extends into space-thus making our Earth similar to a huge magnet. The center of this magnet, the core of the earth allows travelers to use a compass for navigation and directional purposes. This magnet that surrounds the earth does not point exactly north, but slightly off course. However it is not enough that travelers cannot understand the direction.

In past times, travelers depended mainly on the compass to direct them on course. If the compass broke or failed in some way, the travelers could be lost out to sea. This activity will help students understand the concept of magnetism and the compass. The compasses will not fail, but rather, the students will be able to understand the importance of the compass. The students will then connect these ideas to the idea of being lost at sea, in case the compass did fail for some reason.

  1. The students can make a model of the earth, either on paper, or any other way they wish, making sure to note the north and south poles. They can also make sure to have a bar magnet oriented north-south.
  2. After placing the bar magnet on the earth, the students can now make their compass, which they can place onto their ships or use for other purposes.
  3. Rub a needle on the bar magnet, which will attract the needle to the magnet. Push the needle through a small cork and float it in a small dish.
  4. Observe the needle, in relation to the magnet on the model earth, as it is placed around the magnet in each direction of north, south, east, and west.
  5. Because this activity is only a modified example of what a compass can do, allow the students to research other experiment books or books on magnetism. The students may come up with their own activity, which they can share with the class at a later date. Possible experiment books can be found in the reference section of the lesson, but the Internet or other books can also be used.

ASSESSMENT:

  1. Experiment Rubric
  2. Observation Checklist

EXTENSIONS:

  1. Study more about magnetic fields by making a model magnetic field.
  2. Investigate compass directions by discussing the degrees, what directions are found at specific degrees, and other angles.

    --Azimuth

    --Declination

  3. Compare compass directions to celestial observations and how stars can work like a compass.

RESOURCES:

http://www.exploratorium.edu/xref/exhibits/circles_of_magnetism_i.html

Challand, H.J. (1984). Activities in the physical sciences. Chicago: Childrens Press. [ISBN: 0-516-00504-9]

Elementary science experiments. (1971). Compton, CA: Educational Insights. [ISBN: 0-88679-352-1]

 

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