# Magnetic Field Lines

Topics: Magnetic field, Magnet, Ferromagnetism Pages: 6 (1153 words) Published: November 14, 2012
Date: 13.10.2012

Student Exploration: Magnetism

Vocabulary: attract, bar magnet, ferromagnetic, magnetize, North Pole, repel, South Pole

Prior Knowledge Questions (Do these BEFORE using the Gizmo.)

1. What happens when you place two magnets close together? It depends on the sides when the two North Pole sides are meant then they get pulled together. And if it should be the opposite way then they will move each other away.

2. What objects do magnets stick to? Make a list iron and steel, zinc, gold nickel, copper, and brass.

3. What do these objects have in common? They are all made of metal and are so magnetized to the objects shown above this answer.

Gizmo Warm-up: What is attracted to magnets?

A bar magnet is a simple rectangular magnet. If you hang a bar magnet by a string, the north pole (N) of the magnet will tend to point north while the south pole (S) of the magnet points south.

1. Look at the materials at the bottom of the Gizmo™. Which ones do you think will stick to a bar magnet?

Nickel, and Iron.

2. Ferromagnetic materials are strongly attracted to magnets. Drag a bar magnet and the piece of nickel onto the scribbled line. Press Play ([pic]).

A. Is nickel ferromagnetic? Yes

B. How do you know? The atoms in ferromagnetic materials like to align their magnetic dipoles with the external field.

3. Test copper, wood, glass, and iron. Which ones are ferromagnetic? Only the iron is ferromagnetic

|Activity A: |Get the Gizmo ready: |[pic] | | |Check that the Magnetic forces tab is selected. | | |Attract or repel? |Click Reset ([pic]). | |

Question: How do magnets interact?

1. Observe: Drag two bar magnets onto the paper and press Play. Then click Reset. Change one of the magnets (either from N-S to S-N, or vice-versa). Click Play again.

A. What happened the first time? They move apart
B. What happened the second time? They still move apart.

2. Form hypothesis: Magnets are either pulled together (attracted) or pushed apart (repelled). Based on what you have seen, when are magnets attracted and when are they repelled?

North poles are attracted to south poles, but like poles repel. Two north poles or two south poles will invariably push against each other.

3. Predict: Based on your hypothesis, which pairs of magnets will be attracted to each other? Which will be repelled? Record your predictions below. (Leave the result blank for now.)

|Left magnet |Right magnet |Prediction |Result | | | |(Attract or repel?) |(Attract or repel?) | |[pic] |[pic] |Attract |Attract | |[pic] |[pic] |Repel |Repel | |[pic] |[pic] |Repel |Attract | |[pic] |[pic] |Repel |Repel |

4. Run Gizmo: Test your predictions using the Gizmo. Record your results in the table.

5. Draw conclusions: Fill in each blank below with the correct word.

A. The south pole of a magnet is attracted to the north pole of another magnet.

B. The south pole of a magnet is repelled by the south pole of another magnet.

C. The north pole...