CONTENT OBJECTIVE: 6B1.00 To understand the use of magnetism as a force
INSTRUCTIONAL OBJECTIVES: The learner will:
1.01 recall the definition of magnetism.
1.02 explain how magnetic materials differ from non-magnetic materials.
1.03 explain how natural magnets differ from man-made magnets.
I. Definition of magnetism
II. Comparison of magnetic materials to non-magnetic materials
III. Comparison of natural and man-made magnets
TN COMPONENT OF SCIENCE: Habits of Mind
To enable students to demonstrate ways of thinking and acting inherent on the practice of science; and to exhibit an awareness of the historical and cultural contributions to the enterprise of science.
HISTORICAL AND CULTURAL PERSPECTIVE - The knowledge and processes of science have evolved over time as an approximation of truth within cultural contexts.
TN STANDARD(S): The learner will understand that:
3.1c The desire to understand the natural environment and to predict the course of natural events is universal.
BENCHMARK: People have developed theories to explain events.
3.1f Progress in science depends heavily on societal events, and the course of history often depends on scientific and technological developments.
BENCHMARK: Inventions have enhanced our abilities to study science.
Filmstrip, paper clips, iron filings, different types of magnets, nails, teacher-constructed ditto
Today we will discuss magnetism and the types of materials that magnets attract. We will also observe some natural and man-made magnets. Do you recall the different types of magnets? (Yes, horseshoe, and bar) Do magnets attract all objects close to it? (response) Why not? (response) Do you think a man-made magnet is as strong as a natural magnet? Write your response on a piece of paper and put in your desk. At the end of class, we will check your response to see if you were correct.
All matter is made up of atoms. In the atom are two charged particles. These are (+ charged) protons and (- charged) electrons. The electrons spin around the nucleus of the atom which has protons and neutrons (no charge). Magnetism is a force that effects matter. Magnetism is the action force of attracting a certain material by the movement of electrons traveling around the nucleus of an atom. What is the importance of magnetism? (response) Are all materials magnetic? If not, are all metals magnetic? (response) A magnetic material has electrons that spin more in one direction than in the other direction. A non-magnetic material has electrons that spin equally in opposing directions. Natural magnets are called lodestones. They contain iron ore and are considered a permanent magnet. Man-made magnets can be made only from iron, steel, cobalt and nickel. (Show filmstrip.)
(The following activities and associated group discussions on the importance of magnetism are suggested:
1. Make electromagnet from dry cell battery, wire, nail. Pick up paper clips and iron filings with the magnets. Since iron filings are difficult to remove from a magnet, it helps to wrap the magnet in plastic before experimenting. Relate this to a can opener and large magnets used in construction.
2. Use a bar magnet and try picking up different objects. Make a list of identifying traits of the materials. Example: Magnetic materials: iron, steel, nickel, cobalt. Non magnetic materials: copper, zinc, gold, paper, wood, glass.
3. Students can make a man-made magnet. Hang a U-shaped magnet from a ring stand. Put the head of a three centimeter nail in contact with one of the poles of the magnet. Carefully place the head of a second three centimeter nail in contact with the point of first nail and continue until no more can be held on the magnet. Hold the first nail firmly and carefully remove the magnet. Test each nail for magnetism.)
(Teacher-constructed ditto with true/false questions applying to the lesson.)
Today we have discussed how the force of magnetism takes place and traits of magnetic materials and non magnetic materials. Check your response that you wrote earlier on a piece of paper. Is a man-made magnet stronger than a natural magnet? (No) The natural magnet stays magnetized longer.
1. Explain (analyze) how the electromagnet works.
2. Explain the theory of magnetism.
INDEPENDENT PRACTICE OR SUPERVISED PRACTICE:
(The following activities give students the opportunity to research various topics and to have the opportunity to express their findings in their own words.)
1. Define: Magnetism, natural magnet, and man-made magnet.
2. Explain the composition of an atom.
3. Contrast magnetic materials with non-magnetic materials (i.e. composition).
4. Explain (analyze) how the electromagnet works.
5. Design a machine that uses an electromagnet.
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