Phase 1: Modeling Scientific Thinking

Electricity and Magnetism

Erin E. Peters

February 26, 2006

Nature of Science Concept	Examples of Scientific Thinking
Scientific knowledge is durable, yet tentative	William Gilbert in the 1700’s noticed that a piece of iron on top of St. Augustine’s Chapel was magnetic. Gilbert thought that the metal became magnetic because of the winds. In the 1900’s it was found that the piece of metal was magnetic because it was struck by lightning. The lightning magnetized the iron. Ideas in science are usually long-lasting but can sometimes change when new information is introduced.
Empirical evidence is used to support ideas in science	When an inflated balloon rubbed 30 times with wool is brought 1 cm away from paper ripped into 1 cm by 1 cm pieces, the paper is attracted to the balloon. When the same balloon rubbed 30 times with wool is brought 1 cm away from tin foil ripped into 1 by 1 cm pieces, the tin foil is not attracted to the balloon. When the same balloon, rubbed 30 times with wool, is brought 1 cm away from 1 cm by 1 cm Styrofoam pieces, the Styrofoam is attracted to the balloon. Based on these three trials, balloons rubbed with wool attract non-metal objects and do not attract metal objects.
Social and historical factors play a role in the construction of scientific knowledge	All members of the group must help check if observations are complete and truthful because people have different perspectives. Answers are most likely correct if all members of the group agree on an answer. If you think about the ideas that people had in the 1700’s compared to the ideas that we have about magnetism, people in the 1700’s might make different conclusions than we would.
Laws and theories play a central role in developing scientific knowledge, yet they have different functions	When you make sense of your observations, inferences, and ideas, then you are making your own personal theory about electricity and magnetism. When you make further observations, you make sense of the information using your personal theories. Electric charges have certain characteristics because they attract and repel some substances. When I see a magnet repel another magnet, I think about how static electricity works and try to connect it to magnets.
Accurate record keeping, peer review and replication of experiments help to validate scientific ideas	Other people can agree that your observations, inferences and ideas are accurate if they can redo your investigation and find similar observations, inferences and ideas. Scientific knowledge grows when a new idea can be confirmed by the scientific community. I made a magnet out of an iron nail by rubbing the magnet in one direction 50 times. When I did this, the nail, which was not attached to the magnet, picked up 3 paperclips for one minute. When I rubbed the same nail 100 times in one direction, the nail, which was not attached to the magnet, picked up 5 paper clips. I need to perform more trials to confirm the idea that rubbing a metal object more times makes it more magnetic.
Science is a creative endeavor	In order to understand how a magnet becomes less magnetic, I needed to imagine how domains might look. I made a drawing and saw how dropping a magnet might make each domain become scrambled. When fewer domains are lined up, there is less “pulling” from the magnet on another object.
Science and technology are not the same, but they impact each other	Science and technology are used together when testing different materials to see if they conduct electricity. A circuit is built with a space to insert different materials. If the light bulb in the circuit lights up, then the material conducts electricity. The circuit and materials are technology, but the idea of electricity moving around the circuit and changing from electricity to light is science. Technology helps us to think of scientific ideas and scientific ideas help us to make technology better.