Discovering and Analyzing Magnetic Fields with Solenoids 1Running head: DISCOVERING AND ANALYZING MAGNETIC FIELDS WITH SOLENOIDSDiscovering and Analyzing Magnetic Fields with Solenoids in Introductory PhysicsJames KennicuttPhysics 690Discovering and Analyzing Magnetic Fields with Solenoids 2AbstractUnderstanding electricity and magnetism is often difficult for students in many physics courses. Constructing solenoids using a D-Cell flashlight battery, copper wire, a nail, and a straw can help students understand this difficult topic. This activity is designed to help students experience magnetic phenomena and visualize magnetic fields around a current-carrying wire. Students also learn about the changes in intensity of magnetic fields at different distances away from the solenoid and when an iron core is introduced into the solenoid.Discovering and Analyzing Magnetic Fields with Solenoids 3Discovering and Analyzing Magnetic Fields with Solenoids in Introductory PhysicsJames Kennicutt Dept. of Physics, SUNY-Buffalo State College, 1300 Elmwood Ave, Buffalo, NY 14222 <[email protected]>Abstract:Understanding electricity and magnetism is often difficult for students in many physics courses. Constructing solenoids using a D-Cell flashlight battery, copper wire, a nail, and a straw can help students understand this difficult topic. This activity is designed to help students experience magnetic phenomena and visualize magnetic fields around a current-carrying wire. Students also learn about the changes in intensity of magnetic fields at different distances away from the solenoid and when an iron core is introduced into the solenoid.Acknowledgement: This manuscript partially fulfilled requirements for PHY690: Master's Project at SUNY- Buffalo State College, advised by Dr. Dan MacIsaac.Discovering and Analyzing Magnetic Fields with Solenoids 4In my experience teaching introductory physics for high school students, I’ve noticed that students tend to struggle with the concept of magnetic fields and the effects of electromagnetism. Being able to visualize magnetic fields in three dimensions is a significant challenge students face (Nguyen, 2005). The ability to fill in empty space withwhat a magnetic field may look like is a difficult task for students (Sawicki, 1997). In order to help students understand this topic, it is important to provide them the opportunity to gain visual and kinesthetic experience with electromagnetism (Arons, 1997). Allowing students to construct models of a solenoid (or a wire wrapped in a coil) can be beneficial for helping students with visualizing magnetic fields (MacIsaac, 2009) (Picture 01). The goal is to create an interactive activity for students to help them understand how these fields behave and interact with the world around them; as well as gain the hands-on experience that has been proven to help students understand magnetism. This simple activity of constructing low cost solenoids provides students experience with magnetic phenomena and is designed to increase their spatial understanding of three-dimensional magnetic fields. Depending on the level of comprehension you are expecting from your students, this activity would be appropriate for various curriculum levels. The activity is designed for an introductory high school physics class but can be modified to fit the needs of a conceptual physics, AP physics, or even a calculus-based introductory college physics course. The activity will facilitate the exploration of the interactions of solenoids with different materials and the effects different designs have on the magnetic fields generated. Prior to this solenoid construction activity, I covered the basic theory of magnetic fields surrounding permanent magnets and current carrying wires using various activities.Discovering and Analyzing Magnetic Fields with Solenoids 5(Diagram 02, Diagram 03). For help understanding these concepts, students utilized a magnetic compass and iron filings to view the magnetic field around a vertical current carrying wire (Modeling Curriculum, E&M Unit 4 Lab 1 v 3.0).<-- Dan How Do I Cite This? This activity was designed to help students become familiar with magnetic fields as well as introduce them to the Right Hand Rule #2 (Diagram 04). Another activity used iron filings and a compass to view the magnetic field around permanent magnets. Students placed a compass at various distances from a single permanent magnetto observe how the magnet attracted and repelled the north and south poles of a compass. This was a great activity for students to see how the needle of the compass deflected greatly when close to the magnet and deflected only slightly when placed a foot away (Riveros & Betancourt, 2009). Other topics covered included magnetic fields created bya current running through a circular wire and work problems using the Right Hand Rules to determine the direction the magnetic field is pointing inside, outside, and around a current carrying wire in a loop (Knight, 2008). After I completed these introductions, I felt my students were prepared to construct a solenoid and predict its magnetic field.Activity materials required were both inexpensive and readily available. For each student or team, the following materials were required: A length of straw, some magnet wire (enamel coated copper wire - about a meter or yard per person), an iron nail (about 9cm long), a D-Cell, a magnetic compass, and a few paper clips (Picture 01). Although magnet wire works best for winding solenoids, ordinary insulated solid copper wire is acceptable. These materials were purchased at a variety of local stores or on the Internet. Because compasses, paper clips and D-cells were readily available, the cost was roughlyDiscovering and Analyzing Magnetic Fields with Solenoids 6$10 for a class of 25 students. Otherwise, this activity would have cost upwards of $50 (see product list). Many of these materials were able to be recycled for future classes.Constructing the solenoids was quite straightforward. When I began the experiment, I made sure that both ends of the copper wire were stripped. I then asked my students to wrap the wire around the straw with the nail placed inside for support. I instructed my students to note the number of times they wrap the wire loops around the straw for subsequent calculations. To elicit discussions between partners regarding the number of loops vs. the magnetic field strength, I had my students purposely wrap
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