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Formative Assessment: Magnets

What is Magnetism? 

A magnet is an object or material that produces its own magnetic field. Magnets are dipoles meaning they have two poles: a north and a south. Opposite poles (north and south) attract while similar poles (north and north, south and south) repel each other. Magnetism is the force that attracts or repels objects within the magnetic field.

“Magnets” by National Energy Education Development Project is public domain

A magnetic field is the area around a magnet that has magnetic force. The image, below, shows the two poles of a bar magnet and the magnetic field it generates.

“Bar Magnet” by Geek3 is licensed under CC BY-SA 3.0

For further explanation of magnetism, watch the following video:

Video credit: “Introduction to Magnetism” by Khan Academy is licensed under CC BY-NC-SA 3.0. Note: All Khan Academy content is available for free at khanacademy.org.

It is a common misconception that all metals are magnetic–only certain metals become magnetized when exposed to a magnetic field. These include iron, nickel, and cobalt.

All matter is made up of atoms. Electrons, negatively charged particles, move around the nucleus of an atom. The movement of electrons generates a magnetic field. In most atoms, electron pairs move in opposite directions so they cancel each other out. Metals like iron, however, have unpaired electrons. When exposed to a strong magnet, these electrons in the iron line up and act like tiny bar magnets. Thus, the iron is magnetized.

The image, below, shows a bar magnet surrounded by iron filings. The electrons in the iron atoms line up and the iron becomes magnetized when it is exposed to the bar magnet so we can see the shape of the magnetic field.

“Iron Filings” by Dayna Mason is licensed under CC BY-NC-SA 2.0

If you have a stainless steel refrigerator, you may have noticed that magnets do not stick to the front. Although steel is made from iron (a magnetic metal), the stainless steel in refrigerators is usually mixed with other metals to make it more durable. This changes the structure of the metals so the stainless steel is not magnetic.

Key Takeaways

All metals are NOT magnetic. Metals that can become magnetized are

  • Iron
  • Cobalt
  • Nickel

Earth’s Magnetic Field

Earth is surrounded by a giant magnetic field called the magnetosphere. Earth has a solid iron core surrounded by liquid iron. As the liquid metal moves around, it generates an electric current which creates a magnetic field around the planet between the geomagnetic poles. As seen in the image, below, the Earth’s geomagnetic poles are tilted from the North and South poles.

“Earth’s Magnetic Field” by NASA is public domain

Earth’s magnetic field is critical to life on Earth because it protects the planet from the Sun. The Sun produces solar wind which moves extremely quickly through space. As seen in the image, below, the solar wind is strong enough to shape Earth’s magnetic field; it is flatter on the front and cone shaped on the backside of the planet. Still, the magnetosphere protects Earth from the strongest effects of the solar wind.

“Earth’s Magnetosphere” by NOAA is public domain

Compasses

Compasses are used to navigate because their needle points to the magnetic north pole. Historians believe that ancient Chinese civilizations used magnetic compasses in the 11th or 12th century. Later, European explorers used compasses to navigate around the world.

The design of early compasses was simple. First, a needle was rubbed along a magnet to magnetize it. Then, the needle was placed on a piece of cork which floated in a bowl of water. This allowed the needle to spin freely and orient to magnetic north.

It isn’t well understood, but scientists also believe that certain animals like whales, turtles, and bees use Earth’s magnetic field to navigate. This is how they are able to travel long distances without getting lost.

Auroras

Auroras are displays of light in the sky. In the Northern Hemisphere this is known as the aurora borealis; in the Southern Hemisphere is is called the aurora australis. The auroras can be seen in far north and far south locations close to the poles.

“Northern Lights over Alaska” by NASA/Terry Zaperach is public domain

During a solar storm, the Sun sends out a huge cloud of electrified gas which is carried through space by solar wind. Some of these particles get past Earth’s magnetic field and enter the atmosphere at the North and South poles where the atmosphere is thinner. The solar gases interact with the gases in Earth’s atmosphere which causes the light displays. Oxygen causes the lights to show up as green while nitrogen produces a blue or purple aurora.

“Aurora” by NASA Space Place is public domain

For more explanation of the magnetosphere and auroras, watch the following video:

Video credit: “What is an Aurora?” by Michael Molina/TED-Ed is licensed under CC BY-NC-ND 4.0

Performance Expectations:

 

K-PS2-1. <span class="popup" style="cursor: pointer" title="" data-original-title="

Planning and Carrying Out Investigations

Planning and carrying out investigations to answer questions or test solutions to problems in K–2 builds on prior experiences and progresses to simple investigations, based on fair tests, which provide data to support explanations or design solutions.

  • With guidance, plan and conduct an investigation in collaboration with peers.

“>Plan and conduct an investigation to compare <span class="popup " style="cursor: pointer" title="" data-original-title="

Cause and Effect

  • Simple tests can be designed to gather evidence to support or refute student ideas about causes.

“>the effects of <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.A: Forces and Motion

  • Pushes and pulls can have different strengths and directions.
  • When objects touch or collide, they push on one another and can change motion.

PS2.B: Types and Interactions

  • When objects touch or collide, they push on one another and can change motion.

PS3.C: Relationship Between Energy and Forces

  • A bigger push or pull makes things speed up or slow down more quickly.

“>different strengths or different directions of pushes and pulls on the motion of an object.  [Clarification Statement: Examples of pushes or pulls could include a string attached to an object being pulled, a person pushing an object, a person stopping a rolling ball, and two objects colliding and pushing on each other.] [Assessment Boundary: Assessment is limited to different relative strengths or different directions, but not both at the same time. Assessment does not include non-contact pushes or pulls such as those produced by magnets.]
K-PS2-2. <span class="popup" style="cursor: pointer" title="" data-original-title="

Analyzing and Interpreting Data

Analyzing data in K–2 builds on prior experiences and progresses to collecting, recording, and sharing observations.

  • Analyze data from tests of an object or tool to determine if it works as intended.

“>Analyze data to determine if <span class="popup" style="cursor: pointer" title="" data-original-title="

ETS1.A: Defining Engineering Problems

  • A situation that people want to change or create can be approached as a problem to be solved through engineering. Such problems may have many acceptable solutions.

“>a design solution works as intended <span class="popup" style="cursor: pointer" title="" data-original-title="

Cause and Effect

  • Simple tests can be designed to gather evidence to support or refute student ideas about causes.

“>to change <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.A: Forces and Motion

  • Pushes and pulls can have different strengths and directions.
  • Pushing or pulling on an object can change the speed or direction of its motion and can start or stop it.

“>the speed or direction of an object with a push or a pull.* [Clarification Statement: Examples of problems requiring a solution could include having a marble or other object move a certain distance, follow a particular path, and knock down other objects. Examples of solutions could include tools such as a ramp to increase the speed of the object and a structure that would cause an object such as a marble or ball to turn.] [Assessment Boundary: Assessment does not include friction as a mechanism for change in speed.]

 

3-PS2-3. <span class="popup" style="cursor: pointer" title="" data-original-title="

Asking Questions and Defining Problems

Asking questions and defining problems in grades 3–5 builds on grades K–2 experiences and progresses to specifying qualitative relationships.

  • Ask questions that can be investigated based on patterns such as cause and effect relationships.

“>Ask questions to determine <span class="popup" style="cursor: pointer" title="" data-original-title="

Cause and Effect

  • Cause and effect relationships are routinely identified, tested, and used to explain change.

“>cause and effect relationships <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.B: Types of Interactions

  • Electric, and magnetic forces between a pair of objects do not require that the objects be in contact. The sizes of the forces in each situation depend on the properties of the objects and their distances apart and, for forces between two magnets, on their orientation relative to each other.

“>of electric or magnetic interactions between two objects not in contact with each other. [Clarification Statement: Examples of an electric force could include the force on hair from an electrically charged balloon and the electrical forces between a charged rod and pieces of paper; examples of a magnetic force could include the force between two permanent magnets, the force between an electromagnet and steel paperclips, and the force exerted by one magnet versus the force exerted by two magnets. Examples of cause and effect relationships could include how the distance between objects affects strength of the force and how the orientation of magnets affects the direction of the magnetic force.] [Assessment Boundary: Assessment is limited to forces produced by objects that can be manipulated by students, and electrical interactions are limited to static electricity.]

 

3-PS2-4. <span class="popup" style="cursor: pointer" title="" data-original-title="

Asking Questions and Defining Problems

Asking questions and defining problems in grades 3–5 builds on grades K–2 experiences and progresses to specifying qualitative relationships.

  • Define a simple problem that can be solved through the development of a new or improved object or tool.

“>Define a simple design problem <span class="popup" style="cursor: pointer" title="" data-original-title="

Interdependence of Science, Engineering, and Technology

  • Scientific discoveries about the natural world can often lead to new and improved technologies, which are developed through the engineering design process.

“>that can be solved by applying scientific ideas <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.B: Types of Interactions

  • Electric, and magnetic forces between a pair of objects do not require that the objects be in contact. The sizes of the forces in each situation depend on the properties of the objects and their distances apart and, for forces between two magnets, on their orientation relative to each other.

“>about magnets.* [Clarification Statement: Examples of problems could include constructing a latch to keep a door shut and creating a device to keep two moving objects from touching each other.]
MS-PS2-3. <span class="popup" style="cursor: pointer" title="" data-original-title="

Asking Questions and Defining Problems

Asking questions and defining problems in grades 6–8 builds from grades K–5 experiences and progresses to specifying relationships between variables, and clarifying arguments and models.

  • Ask questions that can be investigated within the scope of the classroom, outdoor environment, and museums and other public facilities with available resources and, when appropriate, frame a hypothesis based on observations and scientific principles.

“>Ask questions about data to determine <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.B: Types of Interactions

  • Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distances between the interacting objects.

“>the factors <span class="popup" style="cursor: pointer" title="" data-original-title="

Cause and Effect

  • Cause and effect relationships may be used to predict phenomena in natural or designed systems.

“>that affect <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.B: Types of Interactions

  • Electric and magnetic (electromagnetic) forces can be attractive or repulsive, and their sizes depend on the magnitudes of the charges, currents, or magnetic strengths involved and on the distances between the interacting objects.

“>the strength of electric and magnetic forces. [Clarification Statement: Examples of devices that use electric and magnetic forces could include electromagnets, electric motors, or generators. Examples of data could include the effect of the number of turns of wire on the strength of an electromagnet, or the effect of increasing the number or strength of magnets on the speed of an electric motor.] [Assessment Boundary: Assessment about questions that require quantitative answers is limited to proportional reasoning and algebraic thinking.]
MS-PS2-5. <span class="popup" style="cursor: pointer" title="" data-original-title="

Planning and Carrying Out Investigations

Planning and carrying out investigations to answer questions or test solutions to problems in 6–8 builds on K–5 experiences and progresses to include investigations that use multiple variables and provide evidence to support explanations or design solutions.

  • Conduct an investigation and evaluate the experimental design to produce data to serve as the basis for evidence that can meet the goals of the investigation.

“>Conduct an investigation and evaluate the experimental design to provide evidence that <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.B: Types of Interactions

  • Forces that act at a distance (electric, magnetic, and gravitational) can be explained by fields that extend through space and can be mapped by their effect on a test object (a charged object, or a ball, respectively).

“>fields exist between objects <span class="popup" style="cursor: pointer" title="" data-original-title="

Cause and Effect

  • Cause and effect relationships may be used to predict phenomena in natural or designed systems.

“>exerting forces on each other <span class="popup" style="cursor: pointer" title="" data-original-title="

PS2.B: Types of Interactions

  • Forces that act at a distance (electric, magnetic, and gravitational) can be explained by fields that extend through space and can be mapped by their effect on a test object (a charged object, or a ball, respectively).

“>even though the objects are not in contact. [Clarification Statement: Examples of this phenomenon could include the interactions of magnets, electrically-charged strips of tape, and electrically-charged pith balls. Examples of investigations could include first-hand experiences or simulations.] [Assessment Boundary: Assessment is limited to electric and magnetic fields, and limited to qualitative evidence for the existence of fields.]

DCI:

Kindergarten

PS2.A: Forces and Motion

PS2.B: Types of Interactions

PS3.C: Relationship Between Energy and Forces

 

Third Grade

PS2.B: Types of Interactions

 

Middle School

PS2.B: Types of Interactions

PS2.B: Types of Interactions

Crosscutting:

Cause and Effect

 

Lesson Ideas:

Have children explore different objects with magnets. Can they make a statement about what things stick to magnets? Predict what will or won’t stick and try it out. Try going for a magnet hunt around the classroom with magnet to find objects that stick to magnets.

 

Can  you make magnets move objects at a distance? How far can you get?

 

 

 

definition

License

Magnetism Copyright © 2019 by Dr. Ted Neal and Jeff Nordine. All Rights Reserved.

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