ALEX Learning Activity

The video clip provides step-by-step instructions to implement the inquiry portion of the learning activity in the science classroom. Students will create a model that will illustrate Earth's magnetic field and demonstrate its measurable effects.

• Students will develop a model of Earth's magnetic field.
• Students will use this model to explain how Earth's magnetic field provides protection from cosmic radiation.

The linked video clip demonstrates the step-by-step process of creating and utilizing the model of Earth's magnetic field. 

1. Students will begin by setting up their inquiry. It is recommended that students be divided into collaborative groups of four to five people for this learning activity.
2. Students will place a white sheet of paper or a white paper plate inside of a gallon size bag. The teacher should pour approximately one teaspoon of iron filings or magnetic metal chips into each group's bag. Only place these on one side of the paper or plate. Carefully seal the bag. Alternatively, the teacher could complete this step prior to teaching the lesson.
3. Students will need a copy of the "Earth's Magnetic Shield Inquiry Activity" student sheet. Ask students to create a sketch showing what they think will happen when they place the dipole bar magnet under the plastic bag with iron filings. Students will also write their prediction on their student sheet.
4. After students have completed their prediction, ask them to place the bar magnet under the center of their plastic bag, with the white paper or plate and iron filings facing upward. Ask them to sketch and describe the placement of the iron filings. Students may repeat this step several times to see if the placement of the iron filings changes.
5. With the bar magnet placed under the plastic bag, ask students to place their colored paper circle over the bar magnet, in the center of the iron filings. This colored circle represents Earth. Students will add this object to their sketch created in the previous step. 

Note: Be sure that the iron filings/magnetic metal chips do not come into direct contact with the bar magnet. They will stick to the magnet and be very difficult to disconnect.

The teacher will informally assess students as they complete the inquiry to be sure the procedures are followed accurately. 

The students will be formally assessed by completing the "Earth's Magnetic Shield Reflection Questions" handout to explain how Earth's magnetic field provides protection from cosmic radiation. The teacher can count this assessment as a course grade or use this reflection handout to facilitate a class discussion on the model.

For Teacher Use: "Earth's Magnetic Shield Reflection Questions" Answer Key

Teacher Background Information: Earth's outer core consists of liquid metal, mainly iron and nickel. Due to the intense heat emanating from the solid metal inner core, convection currents are created in the molten metal of the outer core. Convection currents occur when the liquid metal of the outer core is heated, becomes less dense, and rises, as the molten metal rises away from the heat of the inner core, it cools, becomes denser, and sinks. These continuous convection cycles, along with the force created by Earth's rotation, generate electric currents which produce Earth's magnetic field. Although it is not necessary for students to possess this background information to complete this inquiry-based lesson, it would be beneficial to introduce these concepts to students before teaching this lesson. Alternatively, the teacher could extend this lesson by teaching these concepts after the inquiry.

This video clip provides information about the magnetic field created by the outer core: "The Mystery of the Earth's Core Explained" from DNews on youtube.com

The teacher should be sure to gather the materials needed for this learning activity prior to implementing it in the classroom:

Student Materials: Per group of four students

• Dipole bar magnet 
• Gallon-sized plastic bag (for example, Ziploc)
• White paper or paper plate
• Iron filings or magnetic metal chips (at least one teaspoon per group)
• Round piece of colored paper (cut to a diameter the same length of the bar magnets)

Student Materials: Per Student

• "Earth's Magnetic Shield Inquiry Activity" Student Sheet
• "Earth's Magnetic Shield Reflection Questions" Assessment Sheet
• Pencil or pen

Student Background Information: Students should have a basic understanding of magnetism and know that magnetized objects can be attracted to or repelled from each other. Students should also know that the Earth is similar to a magnet, in that it has two poles: one that is positively charged and one that is negatively charged. If students do not have experience with the forces of magnetism, it would be helpful for the teacher to allow students to explore the attracting and repelling forces of dipole magnets.

To expand student understanding of the concepts introduced in this learning activity, the teacher can implement this lesson in its entirety or incorporate the extension activities. 

"Earth's Magnetic Shield: An Inquiry-Based Lesson"

For more information about how this learning activity corresponds to the Next Generation Science Standards and incorporates three-dimensional learning, please visit "Earth's Magnetic Shield: Incorporating Three-Dimensional Learning".