Study guide: Magnets and Noncontact Forces
Distinguish attraction, repulsion and evidence from supplied models.
Ideas to explain in your own words
- Magnets can interact without touching. Like magnetic poles repel and unlike poles attract. Magnetism does not attract every metal; supplied materials must be checked by evidence.
- A bar magnet has north and south poles. Cutting a magnet does not isolate a single north pole in this elementary model; each piece has both poles.
- A fair comparison holds distance and magnet constant while changing the material. Do not infer that every shiny or metallic-looking object is magnetic.
- A proposed design should use the interaction needed for its purpose. Supplied arrow diagrams stand in for hardware. Do not use small magnets, batteries or magnetic toys.
Useful vocabulary
- attract
- poles or material move toward each other
- N-S
- opposite labeled poles attract
- material test
- only tested material changes
- attraction design
- opposite poles draw a marker closer
Watch your reasoning
- Check what attract and repel each mean. They describe different clues.
- Check what N-S and N-N each mean. They describe different clues.
- Check what material test and distance test each mean. They describe different clues.
A worked review example
Worked reference-card problem: a card states “poles or material move toward each other”; a second states “poles move away from each other.” The first fits attract and the second fits repel. The reason is the described function or change, not the order of the cards or a favorite name. If their descriptions exchange places, their category labels exchange too. Keep the supplied descriptions attached to the correct case. Worked reference-card problem: a card states “opposite labeled poles attract”; a second states “matching north poles repel.” The first fits N-S and the second fits N-N. The reason is the described function or change, not the order of the cards or a favorite name. If their descriptions exchange places, their category labels exchange too. Keep the supplied descriptions attached to the correct case. Worked reference-card problem: a card states “only tested material changes”; a second states “only separation changes.” The first fits material test and the second fits distance test. The reason is the described function or change, not the order of the cards or a favorite name. If their descriptions exchange places, their category labels exchange too. Keep the supplied descriptions attached to the correct case. Worked reference-card problem: a card states “opposite poles draw a marker closer”; a second states “matching poles push a marker apart.” The first fits attraction design and the second fits repulsion design. The reason is the described function or change, not the order of the cards or a favorite name. If their descriptions exchange places, their category labels exchange too. Keep the supplied descriptions attached to the correct case.
Make a practice plan
- Use an example from Recognize magnetic interactions. Say what happens and point to the clue that helps explain it.
- Complete Use pole labels and correct the specific misconception in its feedback.
- Resolve a changed case from Compare supplied magnetic tests, then combine the four ideas in the transfer task.