MnSTEP Teaching Activity Collection > MnSTEP Activities > Building an Electromagnet

Building an Electromagnet

Summary

Students will demonstrate how an electric current can make an iron object magnetic by building an electromagnet with a steel nail, insulated wire, a simple switch, a battery/cell, and small metal washers. Students predict the number of washers they can gather on the electromagnet and develop other possible ways to increase or decrease the strength of the electromagnet.

Learning Goals

This activity is designed for students to understand that a relationship exists between electricity and magnetism, and the application of electromagnets to everyday uses. Key concepts include the following: whenever electricity flows through a wire, a magnetic field develops around that wire. When there is no flow of electricity flowing (as with an open circuit) the magnetic field is broken. The steel nail becomes a temporary magnet through induction. The vocabulary words induced-without direct contact, and load-the quantity or amount that is carried (or lifted in this case.)The term variable will be reviewed. Students will graph the relationship of the number of winds coiled around the steel nail to the number of washers lifted, and develop a conclusion based on their data.

Context for Use

This activity will be used in a fourth grade public school classroom of 30 students. The students will be grouped heterogeneously in 9-10 groups of 3 or 4 students per group. Skills that will be needed prior to this activity will be graphing and cooperative group roles established. This activity comes towards the end of our unit therefore making it harder to adapt to other settings because of the amount of concepts developed in previous lessons.
Concepts:
-Cell (battery) is a source of electric energy
-All metals are conductors
-An electric current is a pathway that electricity flows
-A closed circuit allows electricity to flow
-An open circuit (or an off switch) stops the flow of electricity
-Safety procedures are expected for all of hands-on activities.

Subject: Physics:Electricity & Magnetism
Resource Type: Activities:Lab Activity

Teaching Notes and Tips

Some common areas of confusion are with the set up in general. In teaching this before, I showed how the electromagnets are constructed. I would not do that now, but just offer suggestions of using what they already know. Be sure to keep the switch open when the electromagnets are not being used because the batteries will drain quickly. I will also have the students document their ideas more often in their journals and develop and construct their own graphs possible during a math class if more time is needed.

Assessment

Student journals will be selected randomly throughout the unit so that there are samples from each group. This will allow me to check individual's work. Group work can be assessed more informally by observation of class participation and contributions.

Standards

Physical Science Strand II.E.2