Students who demonstrate understanding can: Conduct an investigation and evaluate the experimental design to provide evidence that fields exist between objects exerting forces on each other 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.
Official wording from the Next Generation Science Standards (NGSS Lead States, 2013). NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the NGSS were involved in the production of this page, and they do not endorse it. View on nextgenscience.org
A magnet can move a paper clip through a sheet of paper, and a charged balloon can lift tiny bits of tissue before it touches them. Something must exist in the space around these objects to make that happen. Scientists call it a field: a region around a magnet or a charged object where other magnets or charges feel a force.
Students carry out investigations that make these invisible fields detectable. Iron filings sprinkled around a bar magnet line up along curved paths. A compass needle swings when a magnet comes near, even through a book. Strips of tape that have been charged by pulling them apart attract or repel from a distance, as do lightweight charged pith balls.
Just as important is judging the experiment itself. Did the student control the distance? Could air currents have moved the tape? Is there a better way to show the force acts with no contact? The evidence stays qualitative at this level; measuring field strength is not expected.
Many students think a push or pull needs touching. Show a magnet moving a clip through a table to challenge this idea directly.
The filings only show the pattern of the field. The field is there with or without filings.
Magnets attract iron, nickel, cobalt and steel, but not aluminum, copper or gold. A can of soda will not stick to a magnet.
Charged tape and balloons involve electric fields, not magnetism. A charged balloon does not affect a compass.
A student charges two strips of tape and holds one near the other. The second strip swings away before they touch. A classmate says a breeze might have moved it. How could the investigation be improved to give better evidence for an electric field?
Answer: Add a control with uncharged tape, block air currents and vary the distance; if only charged strips move and the effect grows as they get closer, that is strong evidence of an electric field acting without contact.
Set up stations: iron filings over a magnet under a plastic sheet, a compass circuit around a magnet, charged tape strips, and a balloon with tissue scraps. At each station students record what moved, whether anything touched, and one way the setup could fool them.
Assessment often asks students to choose the best evidence that a field exists or to identify a missing control in a described experiment. Practicing critique of sample investigations builds this skill quickly.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: A) A compass needle turns when the magnet is brought near it
The compass turns without contact, which shows a force acting through the space around the magnet.
Answer: D) A steel paper clip
Steel contains iron, which is attracted by magnets. Aluminum, copper and plastic are not.
Answer: field (also accepted: a field, force field)
That region is called a field: a magnetic field around magnets and an electric field around charges.
Answer: B) Repeat with uncharged tape held the same way
If uncharged strips do not move under the same conditions, air is ruled out as the cause.
Answer: A) The pattern of the magnetic field
The filings line up along the field and reveal its shape, crowding near the poles where it is strongest.
Answer: repel (also accepted: they repel)
Like charges repel; opposite charges attract.
Plan and conduct an investigation to provide evidence that an electric current can produce a magnetic field and that a changing magnetic field can produce an electric current.
Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction.
A full lesson with slides, activities and an exit ticket on fields that act without contact, pitched to grades 6-8 and editable in PowerPoint or Google Slides.
Make a lesson βA printable, differentiated worksheet on MS-PS2-5 with an answer key, ready in about a minute.
Make a worksheet βTurn fields that act without contact into a quiz students answer online that marks itself, with a class summary for you.
Build a test βNo. The assessment boundary limits it to electric and magnetic fields, and to qualitative evidence that they exist.
Students judge whether an investigation really shows a non-contact force, spotting things like missing controls, air movement or hidden contact, and suggest improvements.