This is an experiment that replicates what Christa McAuliffe might have observed in the magnetic chamber during her Challenger mission. We have attempted to enhance the magnetic chamber experiment that was never done for the educational demonstrations of STS-51L. This experiment has been modified to increase our knowledge of magnetism science, engineering, and to engage students, teachers, and other audiences.
Based on Texas Education Standards, students are required to understand the fundamental principles involving magnets. Students cover sections involving magnetism in high school classes that correspond to the Texas Standards (1). A magnet is surrounded by a field that exerts the magnetic force. As stated in the discussions in the Challenger Magnet lesson, we know that individual atoms, in a magnetic material like iron, act as small magnets with north and south poles. Initially, because of the random orientations of the atoms, they cancel each other out, and the iron is not magnetic. However, when a magnet is brought close to a piece of iron comprised of individual atoms, those iron-atom magnets align with the nearby magnetic field. Therefore, the north poles of the iron atoms point in the same direction. The lining up makes the iron itself magnetic. It is attracted to the magnetic field brought near it (2). The field is strongest closer to the magnet and is weakest farther away. The magnetic fields of individual iron atoms are so strong that interactions among adjacent iron atoms cause large clusters of them to line up with one another, which are referred to as magnetic domains. Each of these domains is perfectly magnetized and is made up of billions of aligned atoms (3,4).
6) Science concepts. The student knows forces in nature. The student is expected to:
(A) identify the influence of mass and distance on gravitational forces;
(B) research and describe the historical development of the concepts of gravitational, electrical, and magnetic force;
(C) identify and analyze the influences of charge and distance on electric forces;
(D) demonstrate the relationship between electricity and magnetism;
(E) design and analyze electric circuits; and
(F) identify examples of electrical and magnetic forces in everyday life.
Test Objectives for Magnetism
Using a variety of magnets, we will demonstrate the characteristics of attraction and repulsion of like and unlike poles, determining if the strength of the magnet is affected in microgravity, lunar gravity, and Martian gravity. We want to incorporate neodymium and alnico magnets into the experiment. We will also explore lines of force using metal filings and magnets. The neodymium wasn’t used until the mid 80’s. Neodymium magnets are extremely strong and are used for computer hard drives and headphones. They are also used for generators like wind and hydro turbines, making it useful for renewable energy applications. The neodymium magnets come in a variety of sizes such as cube, circle, star, chain, cylindrical, disc-shaped, and paper thin; however, the cylindrical magnets are very responsive to Earth’s magnetic field and relatively inexpensive (5,6). Based on two of the common types of magnets that are primarily used in society today, we want to test their strengths of them and observe what happens to the iron fillings in microgravity, lunar gravity, and Martian gravity. We hope to see how the fields align in the different gravities as a study to aide in future hardware and equipment using magnets in those settings.
The experiment consists of using the Lost Challenger Mission of the Magnetic Chamber Lesson as a base and guide. The initial experiment would have involved using a cubicle chamber, where this one involves using a 20 ounce plastic soda bottle. Because the magnet can be oriented parallel with the pull of gravity, the lines of force pattern formed by a strong magnetic force nulls out the gravity’s influence. This will enable us to observe the result three dimensionally, just as Christa McAuliffe would have in the lesson chamber during January of 1986 (2).
First, the bottle will be soaked in water to remove the label. Next, the bottle will be filled about a fifth full of iron fillings. Plastic test tubes will be used that are sized about ¾ the bottle height and with a diameter capable of allowing a cylindrical magnet’s axle-like insertion to be placed into it. The two types of cylindrical magnets used are neodymium and alnico. Masking tape has been used to wrap around the test tube to seal and secure it to the top of the bottle.
The two different cylindrical magnets will each be inserted into the test tube one at a time (Figure 1). The atoms will line up with the north poles facing one end of the rod and the south poles of the atoms facing the opposite end (2).
The field of the cylindrical magnet projects from the end of the magnet and loops around the iron cylinder’s side. This causes the iron filings to stick out like hair bristles on the ends of the magnets, though they lie flat against the sides of the magnetic cylinder. The overall shape of the filings combine to show approximately the shape of the magnetic field’s lines of force in three dimensions (2). With the inserted magnet in the test tube, the atoms line up with the north poles facing one end of the rod and the south poles of the atoms facing the opposite end. Like the test tube magnet, the iron filings are also rod-shaped, so that each filing has its atoms lined up pointing along the length of the test tube magnetic rod. The field of the cylindrical magnet projects from the end of the magnet and loops around the iron cylinder’s side. This causes the iron filings to stick out like hair brush bristles on the ends of the magnet, though they lie flat against the side of the magnetic cylinder. The overall shapes of the filings combine to show the shape of the magnetic field’s lines of force in three dimensions.
Hopefully, this shape would have been similar to that of Christa’s magnetic chamber. The lost lesson’s iron-like filings would have clustered about the chamber’s magnet in a similar fashion.
- 2 cylindrical magnets: neodymium and alnico-2 inches by ¼ in diameter.
- Clear plastic soda bottle (20 oz)
- Iron filings that cover a fifth of the bottle.
- Masking tape
- Plastic test tube—3/4 the height of the bottle.
- Video camera and/or web cam.
Questions for the various tests can then be asked to students:
- Which magnet was the strongest?
- Describe the magnetic fields for each magnet?
- How did you think microgravity would affect the magnetic fields?
- What did you predict would happen to the filings in Lunar Gravity?
- What about Martian Gravity?
- What are some problems a strong magnetic might have equipment onboard a ship or space probe?
If you would like to have your students carry out further testing the following can be done:
- Use a Magnetic Field observation box that has silicone oil in it. These can be purchased through the different companies that sell science equipment and materials.
- Incorporate other magnets such as samarium or ceramic.
3. McLaughlin, T, Thompson M, Zike D. (2002) Integrated Physics & Chemistry. Glencoe/McGraw-Hill.
4. Hewitt, P. (2002) Conceptual Physics. Prentice-Hall