Adapted from Magnetic Globe, NASA Education and Public Outreach at Sonoma State University and "Mapping Magnetic Field Lines" and "Exploring Magnetic Fields in Your Environment," activities in Exploring Magnetism, The Center for Science Education at the Space Sciences Laboratory, University of California at Berkeley.
Neato-Magneto Planets is a 45-minute activity in which teams of children, ages 11 to 13, have the opportunity to do their own planetary investigations. The teams study magnetic fields at four separate stations: examining magnetic fields generated by everyday items, mapping out a magnetic field using a compass, creating models of Earth's and Jupiter's magnetic fields, and observing aurora produced by magnetic fields on both planets.
These concepts involve more advanced science than previous activities in Jupiter's Family Secrets, and they explore more deeply the science of the Juno mission and the rich information it will return to us. Facilitators who choose to undertake this activity should have a firm grasp of the scientific basis so that misconceptions are not introduced to the children.
What's the Point?
- Many everyday items can generate magnetic fields.
- Magnetic fields around planets are measurable.
- Earth and the giant planets all have strong magnetic fields.
- Jupiter's magnetic field is the strongest of all the planets in our solar system.
- Planetary magnetic fields are generated in their interiors, so they provide clues about a planet’s inside layers and composition.
For each group of 10 to 15 children:
- 1 set of signs printed on card stock and noting the following:
- "Magnetic Fields All Around" (for station 1)
- "Mapping Magnetic Fields" (for station 2)
- "Modeling Neato-Magneto Planets" (for station 3)
- "Polar Halos" (for station 4)
- 3 flat compasses with transparent faces, which can be purchased from Walmart or Arbor Scientific
- 3 Magnaprobes, which can be purchased from Arbor Scientific or Educational Innovations, Inc.
- 2 (3" long) strong magnets such as cow magnets (available from pet/farm supply stores or science education product retailers Edmund's Scientific's and Amazon)
- 2 flat Alnico bar magnets which can be purchased from Edmund Scientific's or Amazon
- A variety of magnetic household materials, such as paper clips, nails, staples, refrigerator magnets, metal spoons, tin-can lids, etc.
- A variety of nonmagnetic household materials, such as a wooden or plastic top, rocks (not lodestone), aluminum foil, copper wire, paper, wood, soda straws, copper pennies, corks, etc.
- 1 cup containing about 100 "clamped" staples (that have been stapled but not to paper)
- 1 (8-9" diameter) paper plate
- 1 (3") Styrofoam ball
- Optional: Computer, speakers, and access to the video of Jupiter's aurora and sounds of Jupiter's magnetosphere and sounds of Earth's aurora
- Images of Jupiter's aurora, printed preferably in color
For each child:
- His/her My Trip to Jupiter Journal or just the relevant "Neato-Magneto Planets" pages
- 1 pencil or pen
For the facilitator:
- Shopping list
- Optional: 1 bell
- If available, four assistants (parents or older children)
- Review the background information and the Facilitator's Guide to Magnetism.
- The activity, as presented, includes a total of four stations and can be used comfortably with four groups of two to four children. Each station contains one type of magnetism investigation. Alter the number of stations as needed based on the number of children participating, providing duplicate stations, if necessary, so that there are enough sets of materials.
- Prepare an area large enough for four stations, allowing enough room for groups of children to gather around each.
- Set up the materials for each station:
- Station 1 : Set out a variety of materials to test: magnetic and nonmagnetic household materials, such as a plastic wind-up toy, a rock, an aluminum foil sheet, refrigerator magnet, metal spoon, etc., and a strong (cow) magnet. Provide a compass or magnaprobe.
- Station 2: Set out two flat Alnico bar magnets and two compasses or magnaprobes.
- Station 3: Provide a cup of clamped staples and a paper plate at each table. Create a "Neato-Magneto planet": Core the Styrofoam ball and place a strong (cow) magnet inside it.
- Station 4: If possible provide access to the video of Jupiter's aurora and sounds of Jupiter's magnetosphere. Set out images of Jupiter's aurora, printed preferably in color. You may also wish to provide sounds of Earth's aurora.
- Set one magnet and compass or magnaprobe aside to demonstrate their use as you introduce the activity.
- Tape the signs so they hang from the front of the table.
1. Tell the children that they will be investigating magnetic fields. Invite them to share what they know about this topic.
- What's a magnet and how do they behave? Magnets are objects, often metal, that produce a magnetic field. Magnets attract or repel other magnetic materials.
- What's a magnetic field? A magnetic field is the invisible field that surrounds magnetic materials.
Add that while magnetic fields are invisible, they can be measured by the force the field exerts on other magnetic materials.
- Why are we discussing magnets when our topic is planets? Many of the planets — including Earth! — have magnetic fields that we can investigate.
- Can anyone think of a tool that responds to Earth's magnetic field? A compass. Has anyone used a compass? Does anyone know how it works?
Facilitator’s Note: The children may have mistaken ideas about magnetism. They may think that magnetism needs to be transmitted through a medium. However, magnetism can travel through a vacuum and indeed, Jupiter's strong magnetic field stretches far into the void of space. This activity builds on basic concepts of magnetism that the children may have already encountered, but assess their level of understanding as you introduce the activity and adjust your explorations accordingly.
2. Explain that a magnet creates a magnetic field that a compass can detect. Demonstrate that a compass must be held in the horizontal position (flat) with the markings facing up. To line the compass up with Earth's magnetic field, they must rotate the compass so that the line marked "N" (for north) on the compass rim matches up with the arrow inside the compass. Demonstrate with a magnet and a compass that the compass needle moves as it is placed near the magnet. Explain that a compass needle is a tiny magnet, and the north or south pole of the needle will be attracted to the opposite pole of a magnetic field. Let the children know they will have the chance to experiment with this for themselves.
3. Share with the children that they are going to investigate magnetic fields! Divide the children into teams of two to four. Each team will visit four stations. Allow approximately 10 minutes for each station and let the teams know when it is time to rotate (perhaps by ringing a bell). Have them follow the instructions for each station provided in their journals; they will also need their pencils to record their observations and hypotheses. While the children are working, the facilitator should visit the different stations to see if the children are having any difficulties. If there are assistants available, they should remain at their tables to help the children.
Facilitator's Note: Have the children use caution when experimenting with magnets! They should not be brought near computers, computer monitors, audio tapes, or other magnetic devices.
- At station 1, the children will test a variety of household objects to see if they detect magnetic fields by the movements of their compass needles. They will find that magnetic fields are generated by magnetic materials (such as magnets and certain kinds of metals).Compass needles move when brought near these magnetic fields.
- At station 2, the children will map the magnetic field of a magnet. They will place the magnet in their journals and pick a random spot on the page to place a compass. They note the direction of north, pick another spot, and repeat. After connecting the lines, they will see a two-dimensional drawing of the magnetic field lines around the magnet.
At station 2, the children use a compass to map the magnetic field lines of an Alnico bar magnet.Credit: NASA.
- At station 3, the children will discover the three-dimensional magnetic field lines surrounding model planets. They sprinkle clamped staples over balls in which magnets have been embedded. The staples are attracted to the magnets and line up along their magnetic field lines to trace its three-dimensional structures.
At station 3, the children will trace the three-dimensional magnetic field lines surrounding model planets with clamped staples, which are magnetically attracted to magnets embedded in the Styrofoam balls.Credit: Lunar and Planetary Institute.
- At station 4, the children will watch videos, listen to audio interpretations, and/or look at images of Jupiter's and Earth's magnetic fields. The children will find that planetary magnetic fields can be detected not only by compasses, but by the radio emissions and aurora they can produce.
5. After the children have finished at all the stations, invite them to share their findings. Discuss each station separately:
- At "Magnetic Fields All Around," which objects generated a magnetic field? How could the children tell? Magnetic fields are generated by magnetic materials (such as magnets and certain kinds of metals).Compass needles move when brought near these magnetic fields.
- Do the children have any hypotheses as to why some objects might generate a magnetic field and others don't?
Facilitator's Note: Magnetic fields are properties of magnets, but they are also created by current moving through an electric circuit or flow within liquid metallic interiors of certain planets.
- At "Mapping Magnetic Fields," what was the shape of the magnetic field they drew? Several lines could be drawn arching from the magnet's north pole to its south pole.
- How did the shape of the field for "Mapping Magnetic Fields" compare to the shape of the field for "Modeling Neato-Magneto Planets?" The magnetic fields had the same shape, except that they were flat (two-dimensional) in "Mapping Magnetic Fields" and had shape (three-dimensional) in "Modeling Neato-Magneto Planets."
- Do you think spacecraft can do the same types of investigations that we just did? Yes!
Explain that Juno will map Jupiter's magnetic fields. Scientists can also observe phenomena related to the magnetic field of Jupiter: images and radio emissions of Jupiter’s northern and southern lights, or aurora.
Share Earth's and Jupiter's Magnetic Fields with the children and invite them to compare their own investigations with the photos.
- Are their models and drawings of a magnetic field similar to the planets' fields? Yes, the "Mapping Magnetic Fields" drawings and the planet's fields have several lines that arch from the magnetic north poles to their south poles.
- Which planet's magnetic field is stronger? Why? Jupiter's is a stronger magnetic field because Jupiter is bigger.
Add that Jupiter's magnetic field is also stronger because the planet spins so fast (its day is 10 hours long, compared to Earth's 24-hour day). Explain that the Juno mission to Jupiter will use a sophisticated instrument (called a magnetometer) to map Jupiter's magnetic field. This information will help scientists infer details about the liquid metallic hydrogen layer that generates its magnetic field. Juno will also take photographs of Jupiter's aurora.
If possible, build on the children's knowledge by offering them a future Jupiter's Family Secrets activity. Invite the children to return for the next activity and discover how Juno's suite of instruments will provide clues about our solar system's formation in From Your Birthday to Jupiter's.
Because magnetic fields channel and sometimes concentrate radiation along the magnetic field lines, they pose considerable danger to spacecraft that have to pass through them. Due to Juno's highly elliptical orbit, the spacecraft will pass above Jupiter’satmosphere and throughradiation belts created by the magnetic field lines. Over the course of 15 months, Juno will experience radiation that is equivalent to more than 100 million dental x–rays.
In order to complete its mission — including measurements of the magnetic field — Juno must be protected. Juno's instruments were designed to specifically withstand Jupiter's radiation long enough to take critical measurements. Most of Juno’s instruments are housed behind titanium shielding to protect them from radiation. Even so, there will bedegradation of some instruments toward the end of the mission.
For more information about the instruments onboard the Juno spacecraft, visit http://www.nasa.gov/mission_pages/juno/spacecraft/.