Lesson Plan

Earth's Magnetic Shield: An Inquiry-Based Lesson

Subject Area

Science

Grade(s)

6

Overview

Students will begin this inquiry-based lesson by accessing their prior knowledge of the positive and negative effects of the sun's energy. Students will be introduced to the concept of space weather, including cosmic radiation and coronal mass ejections, by watching a video clip from the National Science Foundation. Students will use a dipole bar magnet and iron filings to develop a model of Earth's magnetic field. Students will apply their experience from this inquiry to explain how Earth's magnetic field can protect us from space weather.

This lesson results from a collaboration between the Alabama State Department of Education and ASTA.

Science (2015) Grade(s): 6

SC15.6.11

Develop and use models of Earth’s interior composition to illustrate the resulting magnetic field (e.g., magnetic poles) and to explain its measureable effects (e.g., protection from cosmic radiation).

Unpacked Content

UP:SC15.6.11

Vocabulary

  • Interior
  • Inner Core
  • Outer Core
  • Mantle
  • Crust
  • Molten
  • Magnetic field
  • Magnetosphere
  • Magnetic poles
  • Particles
  • Solar wind
  • Cosmic radiation
  • Solar radiation
  • Waves

Knowledge

Students know:
  • The Earth's interior consists of rock and metal. It is made up of four main layers:
    1. the inner core: a solid metal core,
    2. the outer core: a liquid molten core,
    3. the mantle: dense and mostly solid rock, and
    4. the crust: thin rock material.
  • The temperature in the core is hotter than the Sun's surface. This intense heat from the inner core causes material in the outer core and mantle to move around.
  • It is possible that the movements of material deep within the Earth generate the Earth's magnetic field, called the magnetosphere.
  • The Earth has a magnetic field with north and south poles. The Earth's magnetic field reaches 36,000 miles into space.
  • The magnetosphere prevents most of the particles from the sun, carried in solar wind, from hitting the Earth.
  • Cosmic radiation, which includes solar radiation, is energy from space transmitted in the form of waves or particles.
  • The Sun and other planets have magnetospheres, but the Earth has the strongest one of all the rocky planets.
  • The Earth's north and south magnetic poles reverse at irregular intervals of hundreds of thousands of years.
  • Conditions inside the magnetosphere can create "space weather" that can affect technological systems and human activities. Technological systems that can be impacted may include the operations of satellites, the orbits of low-altitude Earth orbiting satellites, communication and navigations systems.

Skills

Students are able to:
  • Develop a model of Earth's internal composition and identify the relevant components.
  • Describe the relationships between components of the model.
  • Use observations from the model to provide causal accounts for events and make predictions for events by constructing explanations.

Understanding

Students understand that:
  • The composition of Earth's interior may produce a magnetic field with effects that can be measured.

Scientific and Engineering Practices

Developing and Using Models

Crosscutting Concepts

Cause and Effect

Primary Learning Objectives

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.

Procedures/Activities

Before Strategy/Engage (20 minutes)

  1. Brainstorm: Ask students to brainstorm a list of positive and negative effects of the sun's energy. Allow students to share and discuss their list with the class.
    Possible answers: The sun's energy helps plants grow and keeps us warm, but the sun's energy can also give you a sunburn or cause skin cancer.
  2. After students share their brainstorm, explain the sun has various weather events in its atmosphere, similar to Earth. Explain that just as Earth's weather can have a negative impact on us, solar/space weather can have a negative impact as well. Show the students the following video clip: "When Nature Strikes-Science of Natural Hazards: Space Weather".
  3. As students view the video clip, ask them to write the possible effects a large coronal mass ejection (CME) could have on planet Earth. Allow students to share their answers with classmates.
    Possible answers: A large CME could cause radio interference and a power grid malfunction. It could also disable satellite, GPS, and communication systems.
  4. After students share their answers, explain that just as they saw in the video, the Earth has a shield to protect it from space weather. This shield is Earth's magnetic field. Tell students they will be creating a model of Earth's magnetic field to demonstrate how it protects us from space weather.

During Strategy/Explore & Explain (30 minutes)

  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 portion of the lesson. 
  2. Students will place a white sheet of paper 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. Carefully seal the bag. Alternatively, the teacher could complete this step before teaching the lesson.
  3. Students will need the "Earth's Magnetic Shield Inquiry Activity" student sheet located in the attachments. 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 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.

After Strategy/Explain & Extend (20 minutes)

  1. Students will use the model they created in the last step of the inquiry to answer reflection questions. These questions will require students to describe how Earth's magnetic field can protect us from cosmic radiation.

Assessment Strategies

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. The teacher can assess student work using the Answer Key.

Acceleration

Students who meet the Primary Learning Objective can conduct research on the aurora borealis (northern lights) and aurora australis (southern lights), which occur when solar particles interact with Earth's magnetic field and atmosphere.  After conducting research, students can present their findings to their classmates. The following websites contain information about the northern and southern lights:

"What causes the aurora borealis or northern lights?": from earthsky.org

"Aurora Borealis: What Causes the Northern Lights & Where to See Them": from space.com

"Auroras: Dancing in the Night" from NASA Earth Observatory

Intervention

Students who do not have prior experience with the forces of magnetism should be given time to explore how magnets interact with each other. The teacher can provide students with two dipole bar magnets and allow students to feel the magnetic forces of attraction and repulsion. 

The teacher should provide assistance to students as they perform the inquiry to ensure the procedures are being followed accurately. 

Approximate Duration

Total Duration

61 to 90 Minutes

Background and Preparation

Background/Preparation

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

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.

Materials and Resources

Materials and Resources

Student Materials: One per group

Dipole bar magnet 

Gallon-sized plastic bag (for example, Ziploc)

White paper

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: One per person

"Earth's Magnetic Shield Inquiry Activity" student sheet

"Reflection Questions" student sheet

Notebook paper

Pencil

Teacher Materials

Reflection Questions Answer Key

Technology Resources Needed

Teacher computer with internet capabilities

Interactive Board or projector

"When Nature Strikes-Science of Natural Hazards: Space Weather" video clip from the National Science Foundation-5:46 minutes

For background information: 

"The Mystery of the Earth's Core Explained" video clip from DNews on youtube.com-3:27 minutes

Informational articles for extension activity:

"What causes the aurora borealis or northern lights?": from earthsky.org

"Aurora Borealis: What Causes the Northern Lights & Where to See Them": from space.com

"Auroras: Dancing in the Night" from NASA Earth Observatory

Approved Date

2016-08-19
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