Investigating How to Create a Stronger Electromagnet

While investigating the electromagnet inquiry lesson the students will:
-Use scientific thinking process to conduct investigations and build explanations: observing, communicating, comparing and organizing.
-Investigate one method of creating a stronger electromagnet.
-Present to their classmates their discoveries in a clear and understandable method through a graph, report, table, or chart.

Lab activity: 60-minute session.
This lesson is appropriate for grades 3-5 with cooperative groups of 2-3 students.
Students should already know concepts of series circuits and should have had several lab experiences with building electromagnets.
Note: This lesson is intended as an investigation/inquiry extension activity after the students have completed Investigation 4, Current Attractions in the Magnetism and Electricity in the FOSS Curriculum.
Students should have had several experiences working with two-coordinate graphs.

Explain to the class that they are going to conduct a controlled experiment on electromagnets. Review that a controlled experiment is one that creates a standard and clearly shows that only one variable is being changed at a time. Emphasize that careful investigating and documenting helps ensure that their experiment's results are accurate.

Display and discuss the use of the materials that each group will receive (see materials list). Then display and discuss the materials that each group may work with in the inquiry-guided activity (see possible inquiry materials list). Ask them to think of how these materials could be used and give them time to dialogue as a group. Next, a reporter for each group will share what their group's investigable question is. Questions should be worded in such a way that is a "how" question and not one that simply asks a yes or no question. For example, a good question would be, "How does the thickness of a wire affect the strength of the electromagnet?"
Discuss as a class how they will record their results on the X and Y-axis of their two-coordinate graph. Remind them to clearly label their independent and dependent variables and to title their graph (see attachment).
Call each group to collect their materials needed for the inquiry and then have them begin their investigation. Due to the excitement of the experiment, groups may forget to collect and document their data. Reminders should be made periodically to record.
When the groups are finished, they will write their conclusions in their science journals. If any group finishes early, they may examine another variable that they would like to investigate. Finally, groups present (or the reporter from each group) their findings to the entire class. Discuss new findings and any misconceptions that students may have had before the investigations occurred. Write these discoveries in the science journal that answers this question, "What was the pattern you saw that strengthened the electromagnet?" The statements may look like this:
-The thicker the wire, the stronger the electromagnet becomes.
-The longer the wire, the more winds that can be made around the core of the electromagnet. More winds means stronger magnetism.
-The larger nails/rivets do not make stronger magnets. (If the number of winds stays constant.)
-Batteries added in a series circuit make a stronger electromagnet.
-Larger batteries make the electromagnet stronger.

Teacher Materials:
-Wire Stripper

Materials Needed for Each Group:
-1 Circuit Base (such as those provided in the FOSS Magnetism and Electricity Kit)
-1 Switch
-50 or more small washers (1 cm in diameter) in a cup
-Investigation Sheet (see attachment) either separate or placed into the student science journals
-D-cell battery (unless the inquiry is battery size)
-Cell holder (more than one will be needed if the inquiry is battery amount)
-1 short 15cm gauge wire to connect between the battery and the switch

Possible Inquiry Materials for Each Group to Choose From and Management Tips
-Inquiry -Wire Thickness: Try to get as many different gauges of wire as possible such as 24, 22, 20 and 18 (FOSS Kit supplies only 24 and 20-gauge wire). These wires should be color-coded to allow for easy distinction between them. The smaller the number, the thicker the gauge of wire it will be. Remember to have at least 1 cm of wire showing on each end to have the ability to make the proper connections. NOTE: Wires used in electromagnets need to be insulated.

-Inquiry - Wire Length: Have a variety of lengths of wire. It would be best to have them in them pre-cut (in the same gauge) lengths of 150 cm, 125 cm, 100 cm, 75 cm, etc.

-Inquiry -Rivet/Nail Length: Have a variety of different rivet/nail sizes to choose from. Rivet/nail length should have at least a 2 cm difference in length (12 cm, 10 cm, 8 cm, etc.)

-Inquiry - Battery Size: Have a number of different battery sizes to choose from. Students should test at least 3 different sized batteries.

-Inquiry - Battery Amount: Students may test to see how the number of batteries affects an electromagnet's strength. Electromagnet Inquiry Graph (Microsoft Word 34kB Aug31 08)

Students will need many hands-on experiences with electromagnets previous to this inquiry lesson. The investigations in the FOSS unit Magnetism and Electricity should give them plenty of practice and background knowledge to be able to have success with the lesson. In the past, I have never created an opportunity for my students to investigate their own questions about what makes an electromagnet strong. Opportunity to do so should provide a much deeper understanding of the subject.

Students can be assessed on their science journal notes, their two-coordinate graphs and teacher observation of their investigation.

3.I.B.3 - The student will know that scientists use different kinds of investigations depending on the questions they are trying to answer.
4.I.B.2 - The student will collect, organize, analyze and present data from a controlled experiment.
4.II.E.2 - The student will demonstrate how a wire and magnet can be used to generate an electric current.