Question

part i:

1. go to http://phet.colorado.edu/en/simulation/magnets - and - electromagnets or google \phet magnets and electromagnets\

red is north pole white is south pole

1. move the compass slowly along a semicircular path above the bar magnet until youve put it on the opposite side of the bar magnet. describe what happens to the compass needle.
2. move the magnet slowly around the compass. describe what happens to the compass needle.
3. why are the small compasses all over the screen darker by the magnet and more transparent far from the magnet?
4. place the compass by the south pole of the magnet. a compass is really a small magnet floating on water. use the knowledge to explain why the red part of the compass points toward the south pole of the magnet.
5. place the compass by the south pole of the magnet. a compass is really a small magnet floating on water. use the knowledge to explain why the white part of the compass points toward the north pole of the magnet.
6. click to \see inside magnet\. describe what is inside the magnet.
7. predict what would happen inside the magnet if the magnet were to break in half. sketch the result below.
8. click on \show earth\. the magnet that is inside the earth has the south pole of the magnet at the geographic north pole of the earth (magnetic south is above canada).

a. use the compass needle to understand. is the diagram on phet true? yes / no
b. explain your answer.

Explanation:

1. As the compass moves along a semicircular path above the bar magnet, the compass needle will rotate to align with the magnetic field lines of the bar magnet. The north - seeking (red) end of the compass will be attracted to the south pole of the bar magnet and vice - versa.
2. When the magnet is moved around the compass, the compass needle will follow the movement of the magnet, rotating to align with the changing magnetic field direction.
3. The small compasses are darker by the magnet because the magnetic field is stronger there, causing a more pronounced alignment of the compass needles. Far from the magnet, the magnetic field is weaker, resulting in less alignment and more transparency.
4. A compass is a small magnet. Opposite poles attract. Since the red part of the compass is the north - seeking pole, it is attracted to the south pole of the bar magnet.
5. The white part of the compass is the south - seeking pole. Opposite poles attract, so it is attracted to the north pole of the bar magnet.
6. Inside a magnet, there are aligned magnetic domains. These domains are regions where the magnetic moments of atoms are aligned in the same direction.
7. If a magnet breaks in half, each half will form a new magnet with its own north and south poles. New magnetic domains will re - arrange to create two separate magnets.
8. a. Yes. b. The compass needle aligns with the Earth's magnetic field. The north - seeking end of the compass points towards the magnetic south pole of the Earth (which is near the geographic north pole). So the diagram on PHET is true as it shows the magnetic south of the Earth's magnet above Canada.

Answer:

1. The compass needle rotates to align with the bar magnet's magnetic field.
2. The compass needle follows the magnet's movement, rotating to align with the changing field.
3. Stronger field near magnet causes more alignment (darker), weaker field far away causes less alignment (more transparent).
4. Opposite poles attract; red (north - seeking) is attracted to the south pole of the magnet.
5. Opposite poles attract; white (south - seeking) is attracted to the north pole of the magnet.
6. There are aligned magnetic domains inside the magnet.
7. Each half forms a new magnet with its own north and south poles.
8. a. Yes. b. The compass aligns with the Earth's magnetic field, and the magnetic south of the Earth is near the geographic north.