Lesson Summary Making the connection between electricity and magnetism can be difficult, especially when discussed in abstract terms.  In this lesson, students build on their experiences from Lesson 7 to manipulate a magnetic coil of wire and build an electromagnet.  The electromagnet is the subject of controlled experiments designed in Lesson 9, conducted in Lesson 10, and reported to the class in Lesson 11.  The activities with motors in later lessons also use the electromagnet – a necessary part of an electric motor. Teacher Background Electromagnets are made by coiling wire around an iron core and then passing electricity through the wire or by just making a coil of wire and then passing electricity through the coil.  Since each loop of wire becomes magnetic when current flows through it, coiling makes the electromagnet stronger; each loop acts as a little magnet and contributes a bit to the total magnetic force.  In this way, extremely powerful magnets can be produced. Iron is the material most commonly used as a core.  Sometimes, the iron core remains slightly magnetized even after the electricity stops flowing through the wire coiled around it.  This is called residual magnetism, and it can create problems for the students’ understanding of electromagnets.  Note:  A few students may falsely interpret residual magnetism as being caused by the wrapping of the wire around the core instead of by the electricity flowing through the wire.  If this becomes an issue with students, challenge them to figure out the source of the residual magnetism.  They can do this by dropping two cores on the floor (this will remove any residual magnetism), then comparing the effect – on a paper clip - of a core that is only wrapped with wire to the effect on a paper clip of a core that is wrapped with wire and connected to the battery. Set-up/Management Tips Prepare materials for distribution.  Student Activity Book (pgs. 27 – 30) includes instructions with pictures for the activity in this lesson. Literacy Support Students draw and label pictures in their science notebooks showing how electricity can make magnetism. Scientific Vocabulary The following words are key vocabulary words that will be introduced in this lesson and reinforced throughout the unit: *residual magnetism *electromagnet