Emily Walak ECE 380-2 Current Attractions Essays - Electromagnetism

Emily Walak ECE 380-2 Current Attractions Big Idea: Electromagnetism is magnetism created by current flowing through a conductor. Electromagnets can be turned on and off. The strength of the magnetism produced by an electromagnet can be varied. Essential Questions: How can you make a magnet that turns on and off? PA Learning Standards S4.C.2.1.1 Recognize or illustrate simple direct current series and parallel circuits composed of batteries, light bulbs (or other common loads), wire, and on/off switches. Vocabulary magnet - an object that sticks to iron electromagnet - a piece of iron with insulated wire wrapped around it core - the material around which a coil is wound coil - a wire wound repeatedly around a central core Resources: FOSS Electricity and Magnetism Kit Materials: Each group needs 1 Rivet 1 electromagnetic wire, 24-gauge, 150 cm 1 short wire, 20 gauge, 15 cm 1 circuit base 1 D-cell, alkaline 1 switch 50 small washers, 1 cm diameter 1 plastic cup For the Class 1 wire stripper 1 magnet, doughnut shaped Grouping: Partners Engage: Tell students, I was thinking about a big old junkyard crane that I once saw. The crane used a big magnet to lift cars and put them on train cars. The crane operator could turn the magnet on and off! Can you make a miniature junkyard crane that turns on and off? Pour a cup of the small washers into one of the wells on a circuit base. Use a magnet, a steel rivet, and the washers to demonstrate the following. Discuss what is happening in each demonstration. Use a doughnut shaped permanent magnet to pick up the washers and move them to the opposite well. Use the magnet to pick up the rivet. Use the rivet stuck to the magnet to pick up the washers. Use the rivet by itself to pick up washers. Tell students, this is a steel rivet, but it isn't a magnet. Can you make a rivet like this into a magnet that will turn on and off? Explore: There is a new longer wire at the materials station for each team. The long wire may be useful for making your rivet into a magnet that turns on and off. Test the rivet for magnetism by trying to move the washers. When students have successfully constructed electromagnets, call for attention and ask students to make sure their switches are open. Ask, how did you make a magnet that could turn on and off? Explain: Tell students, you discovered an electromagnet. An electromagnet is a piece of iron with insulated wire wrapped around it. While electric current is flowing through the wire, the piece of steel becomes a temporary magnet. An electromagnet is made up of a core and a coil. The core is the rivet and the coil is the wire Extend/ Elaborate: Find the best electromagnetic design. Tell the students that just about everyone wound the wire around their rivets in a different way. Challenge them to work in their group to find the best location to wrap the wire on the rivet to make the rounded head of the electromagnet as strong as possible. Set standards for the class. Work with students to set some standards so that everyone will be able to compare results. Students should agree to always use the same number of winds, pick up washers on the head of the rivet, and count the washers lifted to determine the strength of the magnet. Evaluate: Ask each group to report how they wrapped the wire to produce the strongest magnet. They should report that the magnetism is strongest when the wire is wrapped close to the head, particularly between the first rubber washer and the head. Take Home Extension. N/A Reflection: Walk around while students are completing the activity and assist them as needed.