MS-PS2-5: Investigating Evidence for Electric and Magnetic Fields
In plain English: MS-PS2-5 is the NGSS middle school performance expectation that asks students to conduct an investigation and evaluate its design to show that fields exist between objects that push or pull on each other without touching. Students use magnets, charged tape and pith balls, and look for qualitative evidence. It is usually taught in middle school physical science.
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.
Next Generation Science Standards · Disciplinary Core Idea: Motion and Stability: Forces and Interactions · Official standard
Students conduct investigations with magnets, charged strips of tape and charged pith balls, and they evaluate the design of each investigation, to gather evidence that a field exists in the space between objects that push or pull on each other without touching. A field is a region around an object in which another object feels a force without contact. Students cannot see a field, so they look for its effects: a force across an empty gap, a direction that can be mapped at each point in the space, and an effect that disappears when the source is taken away.
The NGSS Clarification Statement says: "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." The Assessment Boundary says: "Assessment is limited to electric and magnetic fields, and limited to qualitative evidence for the existence of fields." So every item on this page is about electric or magnetic fields, and the evidence is qualitative: what moves, which way, and whether it happens without contact. Gravitational fields and measuring how strong a field is are beyond this standard. All data sets are invented for teaching and record counts of trials, not field strengths.
Learning Objectives
By the end of this lesson, students will be able to:
Conduct investigations with magnets, charged tape strips and pith balls that show forces acting between objects that are not touching
Use a compass map to show that a magnet has an effect, with a direction, at every point in the space around it
Evaluate an experimental design: identify the variable tested, the variables kept the same, the controls and the number of trials
Explain why the evidence points to a field and not to another cause, such as hidden contact or moving air
Prior Knowledge Required
Students should already be comfortable with:
Magnets attract some metals and attract or repel other magnets without touching them 3-PS2-3
Forces as pushes or pulls that can change how an object moves
Variables in an investigation: the one you change, the ones you keep the same and the one you observe
Show the class a steel paper clip tied to a thread. The other end of the thread is taped to the table. A bar magnet clamped to a ring stand holds the clip up in the air, about 1 cm below the magnet, with the thread pulled tight.
Warm-Up Prompt
"The paper clip is floating. What is holding it up? Convince a skeptic that nothing is touching the clip. What test would you run, and what result would change your mind?"
Record ideas on the board without judging them. Students often say "magnetism" without saying what is in the gap. Ask: "If nothing touches the clip, how does the magnet push or pull on it from over there?" Introduce the word field and tell students that today they will collect evidence that fields are real, and judge how good that evidence is.
Direct Instruction15 minutes
Key words. A field is a region around an object in which another object feels a force without touching it. A magnetic field surrounds a magnet. An electric field surrounds an object with electric charge. An object becomes charged when rubbing or pulling apart two materials moves tiny particles called electrons from one to the other. A pith ball is a very light ball (made from plant pith, or foam) hanging on a thread, used to detect electric forces. A control is a trial in which the suspected cause is removed, so you can see what happens without it.
Evidence for a field. We cannot see a field, so we look for its effects: (1) a force acts across an empty gap, with no contact; (2) the effect has a direction at each point in the space around the object; (3) the effect disappears when the source is removed or uncharged. Evaluating a design means asking: Was there really no contact? Was only one thing changed? Were there controls that rule out other causes, like moving air? Were there enough trials?
Magnet: a push or pull across a gap (first-hand)
A steel ball bearing sits on a table. A bar magnet is slowly moved toward it. The ball rolls toward the magnet while the gap is still about 2 cm, in 5 of 5 trials. A wooden block of the same size, moved the same way, does not move the ball in any of 5 trials.
Result: Evidence: the ball starts to move before anything touches it. The wooden block is a control: it moves the air and casts a shadow just like the magnet, but the ball stays still. So the cause is something about the magnet that reaches across the gap.
Magnet: mapping the space with compasses
Fourteen small compasses are placed around a bar magnet (Diagram 1). The needles point in different directions, curving from the N end of the magnet around to the S end.
Result: Evidence: at every spot in the space around the magnet, something turns the needle in a definite direction, without touching it. This pattern of directions is a map of the magnetic field.
Electric: charged strips of tape
Two strips of clear tape are pressed onto a table, then quickly peeled up and hung from the table edge. Two strips that were each the bottom of a stuck pair (B and B) swing apart before they touch. A top strip (T) and a bottom strip (B) swing toward each other but stop without touching (Diagram 2).
Result: Evidence: charged strips push or pull on each other across a gap of air. Like charges push apart and opposite charges pull together. The force acts without contact, so it is evidence of an electric field around each charged strip.
Electric: a charged pith ball
A pith ball hangs from a thread on a ring stand. A plastic straw is rubbed with a paper towel and brought slowly toward the ball. The ball swings toward the straw while it is still about 3 cm away. If the ball touches the straw, it may pick up charge and then be pushed away.
Result: Record only what happens before contact. The ball moves toward the straw across an empty gap, which is evidence of an electric field around the charged straw. What happens after contact is a different event and cannot count as no-contact evidence.
Evaluating a design
A student wants to show that a magnet turns a compass needle without contact. He sets the compass on a steel desk, holds it in his hand, slides the magnet until it bumps the compass, and tests once.
Result: Weaknesses: the steel desk can turn the needle by itself; the bump means there was contact; his hand may move the compass; one trial could be luck. Better design: a wooden table, the compass set down and not held, the magnet stopped 5 cm away, and at least 5 trials.
After each example, ask: "What is the evidence? What other explanation could there be, and which part of the design rules it out?"
Guided Practice15 minutes
Pairs analyze invented results from a class investigation with a pith ball and a strip of tape. In each trial, a student moved the tape (or only her hand) toward the hanging ball at the same slow speed and stopped 3 cm away. The class recorded whether the ball moved before anything touched it.
Guided practice data (invented): did the pith ball move before contact?
Condition
Trials
Ball moved before contact
1. Charged tape strip (just peeled from the table)
10
10
2. Same strip after running it gently between damp fingers
10
0
3. Hand only, no tape, moved the same way
10
1
4. Charged tape strip, ball inside a clear box with an open front
10
9
Name the condition that tests the main idea and the conditions that are controls.
For each control, write one other explanation it helps rule out.
Condition 3 moved the ball once. Should the class worry about that one trial? What does it suggest the class should keep doing?
Write a claim about the space around the charged tape, with evidence from two conditions.
Independent Practice10-15 minutes
Design critique. Each student reads this plan and writes a short evaluation: "I want to show that a magnet's field passes through different materials. I will hold a small magnet over a paper clip and slide in paper, cardboard and foil. I will use a different magnet for each material because the first one is in use. I will do each material once and write down whether the clip jumped up. If the clip sticks to the material, I will count that as a yes." Students list at least three problems, explain why each one weakens the evidence, and rewrite the plan so that it gives strong evidence. Then they trade with a partner and check each other's rewrite against the four design questions from Direct Instruction.
Closure5 minutes
Exit ticket: "Describe one observation from today that shows a force acting across empty space. Then name one part of the investigation's design that made you trust that observation." Return to the warm-up and ask whether anyone would now change their test for the floating clip.
Differentiation Strategies
For Struggling Students
Give a three-column observation table (setup, what moved, was there contact?) so every trial is recorded the same way
Start with magnets, which work every time, before the tape and pith balls, which are affected by humid air
Give a design checklist with four boxes: no contact, one change, a control, several trials
For Advanced Students
Ask students to design a control that rules out the idea that the floating clip is held up by the thread instead of by the magnet
Have students compare the compass map from a simulation with their own compass map and explain any differences
Ask students to argue whether a compass map is evidence of a field or only evidence of a force, and what would convince a skeptic
Assessment Guidance
What to Look For
Check that students separate observations made before contact from those made after contact, and that they name a specific other explanation (moving air, a touch, a charged hand) for each control they describe. Look for designs that change only one thing and repeat trials. Listen for students who say a field is "the magnet's power" or "air": push them to describe the evidence that something acts in the empty space. The evidence on this page is qualitative: students do not need to measure the strength of a field.
02
Classroom Activities
3 Activities
1
Floating Paper Clip: Through the Barrier
20 minGroups of 3
Groups set up the floating paper clip from the warm-up and slide different materials into the gap between the magnet and the clip, without touching the clip. They record whether the clip stays up, run three trials per material, and then evaluate their own design.
Procedure
Clamp a ceramic bar magnet to a ring stand. Tie a thread to a paper clip and tape the other end to the table so that the clip floats about 1 cm below the magnet.
Slide each material into the gap: paper, cardboard, a plastic ruler, a wooden craft stick, aluminum foil and a steel jar lid. Do not let the material touch the clip.
Record "stays up" or "falls" for 3 trials per material. Use the same magnet, clip, thread length and gap every time.
Safety: keep magnets away from phones and computers, never put small magnets near your mouth, and handle the jar lid by its rolled edge.
Sample Data (invented)
Paper, cardboard, plastic ruler, craft stick and aluminum foil: the clip stayed up in 3 of 3 trials each. Steel jar lid: the clip fell in 3 of 3 trials.
Discussion Questions
Five of the six materials did not stop the clip from floating. What does that tell you about what is in the gap?
Steel is a material that magnets attract. Suggest why the steel lid made a difference when the others did not.
Look back at your design. How did you make sure nothing touched the clip? What would you change if you ran the test again?
Modification for Distance Learning
Students use a refrigerator magnet and a paper clip on a thread taped to a book, test household materials and post a table and a photo of their setup.
2
Tape and Pith Ball Investigation with Controls
25 minPairs
Pairs investigate electric forces with strips of tape and a pith ball, then plan and run controls that rule out other causes. Each pair writes a short evaluation of its own design.
Procedure
Make a T strip and a B strip: press a 12 cm strip of clear tape on the table (B), press a second strip on top of it (T), then peel the pair up and pull them apart quickly. Hang each strip from the edge of the table by a folded tab.
Bring a new B strip near the hanging B strip, then near the hanging T strip. Record what happens before any contact.
Bring a freshly charged strip toward a pith ball hanging on a thread. Record whether it moves before contact.
Plan and run two controls of your own, for example an uncharged strip or a hand moved the same way. Do at least 5 trials of each condition.
Safety: clear tape and pith balls are safe; work on dry days if possible, because damp air lets charge leak away.
Sample Data (invented)
B strip toward B strip: pushed apart before contact in 6 of 6 trials. B strip toward T strip: pulled together before contact in 6 of 6 trials. Charged B strip toward pith ball: the ball moved toward the strip before contact in 5 of 6 trials; in the other trial the strip touched the ball first, so the pair did not count it as no-contact evidence.
Discussion Questions
Why did the pair leave out the trial in which the strip touched the ball?
Which of your controls was the most convincing to a skeptic, and why?
A B strip and a T strip pulled together, but two B strips pushed apart. What does this tell you about the charges on the strips?
Challenge Variation
Pairs predict, then test, how a charged strip affects a second pith ball hanging next to the first one, and draw arrows showing the direction of the push or pull on each ball.
3
Simulation Field Maps and Design Review
20 minPairs
Pairs use free online simulations, one with a magnet and a compass and one with charges, to map the direction of the effect at many points around a magnet and around a charged object. They compare the simulation with their first-hand results and review another pair's investigation plan.
Procedure
Magnet simulation: drag the compass to at least 10 places around the magnet and sketch the needle at each place. Then flip the magnet and repeat 3 of the places.
Charge simulation: place one charged object, move a small test charge to 8 places around it and sketch the direction of the push or pull at each place.
Compare the magnet map with the compass map from class (Diagram 1). Mark one way the simulation matches and one way it differs.
Trade investigation plans from Activity 2 with another pair and review them with the design checklist: no contact, one change, controls, enough trials.
Discussion Questions
In the magnet simulation, what happened to the needles when you flipped the magnet? What does that tell you about the field?
A simulation is a model that people programmed. What can it show that your first-hand test cannot, and what can your first-hand test show that the simulation cannot?
Which suggestion from the design review would most improve your plan?
Modification for Distance Learning
Students complete both simulation maps at home and post them with a two-sentence comparison to their first-hand data or the class sample data.
03
Diagrams & Visual Aids
2 diagrams
Diagram 1: Compass Map Around a Bar Magnet
Fourteen compasses around a bar magnet. Each needle's red north-seeking end points away from the N end of the magnet and around toward the S end, so the needle directions change smoothly from place to place. Nothing touches the needles. Needle directions are computed from a simple two-pole model of the magnet.
Diagram 2: Charged Strips of Tape Interacting Without Contact
Two B strips push apart and hang with a wide gap at the bottom. A T strip and a B strip pull toward each other but stop before touching. In both pairs the strips are separated by air, so the push or pull acts across an empty gap.
04
Homework Assignment
~30 min
MS-PS2-5 Homework: Evidence for Fields
Directions: All data sets are invented for practice. For each problem, say what the evidence is, whether it was gathered without contact, and how the design rules out other explanations. Use full sentences.
Part 1: Interpreting Investigations (Problems 1-3)
A student places a compass on a table and slides a bar magnet toward it from four different directions, 3 trials from each direction. The needle turned before the magnet touched it in all 12 trials. She then slid a wooden block of the same size the same way, 12 times, and the needle never turned. (a) What is the evidence that something acts in the space around the magnet? (b) What does the wooden block rule out? (c) Why did she test from four directions?
A pith ball hangs from a thread. A class records these trials: a charged straw moved toward the ball, 8 trials, ball moved before contact 7 times; an uncharged straw moved the same way, 8 trials, ball moved 0 times; a charged straw held still 3 cm away for 10 seconds, 8 trials, ball moved toward it 8 times. (a) Which condition is the control? (b) Why is the third condition useful even though nothing is moving toward the ball? (c) What claim do the data support?
Without opening a closed cardboard box, a student places small compasses at six spots around it. The needles point in six different directions. When the box is carried to the other side of the room, all six needles point north. (a) Is this evidence of a field? Explain. (b) What kind of object could be in the box? (c) Describe one more test, without opening the box, that would make the evidence stronger.
Part 2: Designing and Evaluating Investigations (Problems 4-6)
A student rubs a plastic straw with a paper towel and holds it above small bits of tissue paper on a desk. Some bits jump up to the straw. He writes, "This proves electric fields exist." He ran one trial, held the straw in his fist, and moved it quickly. (a) List two weaknesses in this design. (b) Rewrite the plan so that it gives strong evidence of a force without contact.
Plan an investigation to answer: "Does the push between two B strips of tape still happen when a sheet of paper hangs between them?" Include the question, the one thing you will change, what you will keep the same, at least one control, how many trials, how you will check that nothing touches, and how you will record results.
A magnet-and-compass simulation shows needle directions all around a magnet, and your class compass map shows the same pattern. A classmate says, "We do not need the real compasses, because the simulation is enough evidence." Write a response that explains one strength and one limit of each kind of evidence.
Rubric
Criterion
Full Credit (2 pts)
Partial Credit (1 pt)
Evidence of a Field
Identifies a force or effect that acts across a gap with no contact and links it to a field
Describes the effect but does not address contact or the space between the objects
Controls and Alternatives
Names a specific alternative explanation and the control that rules it out
Mentions a control without saying what it rules out
Design Quality
Plan changes one thing, keeps the rest the same, repeats trials and checks for contact
Plan misses one of these features
Communication
Clear sentences, results recorded in a table, claim stated
Claim or table missing, or reasoning hard to follow
05
Quiz: 20 Questions
Interactive, with answers
Instructions
All data sets are invented for practice. A field is a region around an object in which another object feels a force without contact. Your score updates as you answer, and Reset quiz clears everything so you or your students can try again.
Multiple choice: pick an option to check it. Short answer: write your answer, then reveal the model answer.
0 of 20 answered · 0 correct
Question 1 of 20 · Multiple Choice
Which observation is evidence that a field exists between two objects?
Answer: B
The needle turns before anything touches it, so something acts across the gap: a magnetic field. Choices A, C and D all involve objects that are touching, so they cannot show a force without contact.
Question 2 of 20 · Multiple Choice
A paper clip floats on a thread just below a magnet. A student slides a thin piece of felt fabric into the gap without touching the clip, and the clip stays up. What does this observation support?
Answer: A
The clip keeps floating with felt in the gap, so the magnet still acts on the clip through the felt. Choice D is the opposite of what was seen. Choice C is not tested by this observation. Choice B is not shown: nothing says the felt moved toward the magnet.
Question 3 of 20 · Multiple Choice
In a pith ball investigation, why do students also bring an uncharged straw toward the ball, moved the same way?
Answer: C
The uncharged straw is a control: it moves the air and the hand exactly like the charged straw. If the ball stays still, moving air is ruled out as the cause. Choice A would change the ball, not test it. Choice D is not what a control does, and measuring field strength is beyond this standard.
Question 4 of 20 · Multiple Choice
Why should an investigation of charged tape include several trials of each condition?
Answer: A
Repeated trials show whether a result happens reliably, so one odd trial (a breeze, a touch) does not decide the conclusion. Choice B is not the reason, and tape can lose charge over time. Choice C is wrong: trials and controls do different jobs.
Question 5 of 20 · Multiple Choice
A student pinches the bottom ends of two B strips together with her fingers, then lets go. The strips spring apart, and she says, "This proves an electric field pushed them." What is the main problem with her evidence?
Answer: D
Evidence for a field must show a force acting without contact. The strips started out pinched together, so the springing apart could come from her fingers or from the tape bending back. Choice A is false: peeled tape strips become charged. Choice B changes the investigation instead of fixing it. Choice C is wrong: light objects are what make tape good for detecting electric forces.
Question 6 of 20 · Multiple Choice
A class records invented data: charged tape near a pith ball, 12 trials, moved before contact 11 times; uncharged tape moved the same way, 12 trials, 1 time; hand alone, 12 trials, 0 times. Which conclusion do the data best support?
Answer: A
With charge, the ball moved in 11 of 12 trials; without charge, in only 1 of 12, and the hand alone never moved it. So the charge, not the air or the hand, is the cause, and it acts across a gap. Choice B cannot explain why the hand alone did nothing. Choice C contradicts the "before contact" record.
Question 7 of 20 · Multiple Choice
Small compasses around a bar magnet point in many different directions. When the magnet is taken away, every needle points north. What does removing the magnet show?
Answer: B
Taking the magnet away removes the effect, so the magnet is what turned the needles. That is the job of a control. Choice A is ruled out because the compasses work normally once the magnet is gone. Choice D contradicts the setup: the compasses sit apart from the magnet.
Question 8 of 20 · Multiple Choice
Two pith balls are touched by the same charged straw, then hung from threads 4 cm apart. They swing away from each other and hang at an angle, never touching. What does this observation show?
Answer: C
Both balls picked up the same kind of charge from the straw, and they push each other apart while separated by air, so an electric force acts across the gap. Choice A names the wrong kind of field: pith balls are not magnetic. Choice B would need a control to rule it out, and a breeze would not push the two balls in opposite directions. Choice D contradicts the observation.
Question 9 of 20 · Multiple Choice
A group tests whether a charged straw still moves a pith ball when different sheets (paper, cloth, plastic wrap) hang between them. Which variable should stay the same for every sheet?
Answer: B
The distance (along with the straw, the ball and the way the straw is charged) must stay the same so that only the sheet changes. Choice A is the variable being tested. Choice C is the result being observed. Choice D does not affect any single test.
Question 10 of 20 · Multiple Choice
What is one limit of using a simulation as evidence that fields exist?
Answer: A
A simulation is a model: it follows rules that people wrote, so its results count as evidence only when they match real observations. Choice B is false: simulations can show many places at once. Choice C is false: good simulations match real compasses. Choice D is false.
Question 11 of 20 · Multiple Choice
A charged straw makes a pith ball swing toward it, even with a sheet of clear plastic between them. Before claiming the electric effect passes through plastic, which other explanation should the student rule out?
Answer: B
Rubbing or handling plastic can charge it, so the sheet itself might be pulling the ball. A control, such as the sheet alone with no straw, would test this. Choice A is true but does not cause a sideways swing. Choices C and D do not cause the ball to swing toward the straw.
Question 12 of 20 · Multiple Choice
Which result would suggest that a floating paper clip is NOT held up by a magnetic field?
Answer: C
If the clip floats with no magnet, something else (such as a stiff thread) is holding it up, so the magnet's field is not the cause. Choices A and D show that the magnet controls the clip. Choice B shows the effect acting through paper.
Question 13 of 20 · Multiple Choice
A student holds two strips of tape in her hands and brings them together. They swing apart, and she concludes that an electric force pushed them. Which change would most improve her design?
Answer: D
Hanging the strips keeps her hands still and away from them, so their swing can only come from each other. Hand-held strips move whenever her hands move. Choice A and choice B do not address the hand problem. Choice C makes it harder to see what happens before contact.
Question 14 of 20 · Multiple Choice
A magnet held 3 cm above a pile of steel staples lifts several staples up to it. A wooden block of the same shape, held the same way, lifts none. Which claim is best supported?
Answer: D
The staples rise before anything touches them, and the wooden block, which moves the air the same way, lifts none, so the effect comes from the magnet across the gap. Choice C is ruled out by the wooden block. Choice B is not tested here: no wood was placed between the magnet and the staples. Choice A overgeneralizes: aluminum and copper, for example, are not pulled by magnets.
Question 15 of 20 · Short Answer
A magnet under a 2 cm wooden tabletop is moved in a circle, and a steel paper clip on top of the table follows it. Explain how this is evidence of a magnetic field, and describe one control you would add.
The clip moves while 2 cm of wood separates it from the magnet, so the magnet pushes or pulls on it without contact: something in the space around the magnet, a magnetic field, acts on the clip. Control: move a same-size block of wood (or an unmagnetized steel bar) under the table the same way; the clip should not follow. This rules out vibration or the table shaking as the cause.
Question 16 of 20 · Short Answer
Plan a test of whether a magnet's field acts through water. Say what you will change, what you will keep the same, one control and how many trials you will run.
Sample plan: float or hang a paper clip inside a clear plastic cup and hold a magnet outside the cup. Change: whether the cup is empty or full of water. Keep the same: the magnet, the clip, the cup and the distance from magnet to clip. Control: the same setup with no magnet, to show the clip does not move by itself. Run at least 5 trials of each condition and record whether the clip moves toward the magnet before anything touches it.
Question 17 of 20 · Short Answer
A group tested five materials between a magnet and a floating clip, once each, and wrote only "worked" or "didn't work." Give two ways to improve their investigation.
Any two of: run several trials (at least 3) for each material; write what was observed ("clip stayed up," "clip fell") instead of "worked"; keep the gap, magnet and clip the same for every material; check and record that the material did not touch the clip; add a control trial with no material in the gap.
Question 18 of 20 · Short Answer
Two charged tape strips push each other apart. After a student runs each strip gently between damp fingers, they hang straight down side by side and do not move. What does this second test show, and why is it useful?
Removing the charge removed the push. This shows the charge on the strips caused the force, not air, the tape's stiffness or the way the strips were hung. It is useful as a control: the only thing that changed was the charge, so the electric force must come from the charged strips and act across the gap between them.
Question 19 of 20 · Short Answer
In a charge simulation, a small test charge is dragged to eight places around a fixed charged ball. At every place, an arrow shows a push directly away from the ball. Explain why this counts as evidence of an electric field.
The test charge feels a push at every place around the ball, even though nothing touches it, and the push has a definite direction at each place. An effect that fills the space around an object and acts without contact is what a field is.
Question 20 of 20 · Short Answer
A student says, "I can't see anything between the magnet and the floating clip, so there is nothing there." Write a response that uses evidence from an investigation.
Sample answer: Something can be real even if we cannot see it, if we can see its effects. When a magnet is near, compasses all around it turn to point in definite directions without being touched, and they swing back to north when the magnet is removed. The floating clip falls when the magnet is taken away. So something acts in the space around the magnet: a magnetic field.
0 of 20 answered · 0 correct
06
Frequently Asked Questions
10 Questions
What does MS-PS2-5 mean?
MS-PS2-5 asks middle school students to carry out an investigation, and to judge how well it was designed, to gather evidence that fields exist between objects that push or pull on each other without touching. The code stands for Middle School, Physical Science, core idea 2 (Motion and Stability: Forces and Interactions), performance expectation 5.
What is the assessment boundary for MS-PS2-5?
Assessment is limited to electric and magnetic fields and to qualitative evidence for the existence of fields. Students describe what moves, in which direction and whether there was contact. Measuring the strength of a field, field formulas and gravitational fields are beyond this standard.
What is a field in simple terms?
A field is a region around an object in which another object feels a force without touching it. A magnet has a magnetic field around it, and a charged object has an electric field. We cannot see fields, but we can detect them with a compass, a pith ball or a strip of charged tape.
What is a pith ball and what can I use instead?
A pith ball is a very light ball, once made from the soft pith inside plant stems and now usually made of foam, that hangs on a thread and swings when a charged object comes near. Science suppliers sell them. A small foam ball wrapped in aluminum foil, hung on a cotton thread, works in a similar way.
How do you make charged strips of tape?
Press a strip of clear tape onto a table (the bottom strip, B), press a second strip on top of it (the top strip, T), then peel the pair up and pull them apart quickly. The two strips end up with opposite charges. Two B strips push apart, and a T strip and a B strip pull together. Dry air works best.
What makes a good MS-PS2-5 investigation design?
A good design shows that there is no contact, changes only one thing at a time, includes controls that rule out other causes (such as an uncharged strip to rule out moving air, or removing the magnet), repeats each condition several times and records exact observations. Evaluating the design means checking for each of these.
Why do tape and pith ball experiments sometimes fail?
Humid air lets charge leak away, so strips and balls can lose their charge in seconds. Touching the strips or the ball with fingers can also remove charge. Work on dry days if possible, charge the tape again right before each trial, and handle the tape only by a folded tab.
Can simulations count as evidence for MS-PS2-5?
Yes. The Clarification Statement names simulations as one kind of investigation. They are useful for mapping directions at many places at once and for setups that are hard to build in class. When you can, pair each simulation with a first-hand test of the same setup.
How is MS-PS2-5 different from MS-PS2-3?
MS-PS2-3 asks students to ask questions about data on the factors that affect how strong electric and magnetic forces are. MS-PS2-5 asks for evidence that a field exists at all, in the space between objects that are not touching, and for an evaluation of the investigation that produced the evidence.
What comes after MS-PS2-5?
In high school, HS-PS2-5 asks students to investigate how electric currents produce magnetic fields and how changing magnetic fields produce currents, and HS-PS3-5 models the forces and energy of objects interacting through fields. MS-PS3-2, in middle school, connects fields to stored energy.
07
Related Standards
5 standards
These standards connect to MS-PS2-5: prerequisites to review first, parallel standards at the same level, and next steps that build on it.
Before this lesson
3-PS2-3Prerequisite
Ask questions about cause and effect in electric or magnetic interactions without contact
Lesson coming soon
Alongside
MS-PS2-3Parallel
Ask questions about data on factors that affect electric and magnetic forces
NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the Next Generation Science Standards were involved in the production of this product, and do not endorse it.
