Students who demonstrate understanding can: Ask questions about data to determine the factors that affect 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.
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
Electric and magnetic forces can be made stronger or weaker, and the goal here is to figure out what controls them by questioning data. For an electromagnet, more turns of wire around the core, more current through the wire, and an iron core all make the magnet pick up more paper clips. For charged objects, more charge and less distance between them make the push or pull stronger.
The important habit is asking good, testable questions. Instead of 'Why are magnets cool?', students ask 'How does the number of coils affect how many paper clips the electromagnet lifts?' and then look at the data to answer it. Devices such as electric motors and generators give a real context: a motor spins faster with stronger magnets or more current.
When questions need numbers, the reasoning is proportional: if 10 turns lift 6 clips and 20 turns lift about 12, doubling the turns roughly doubled the effect. More complex formulas are not expected.
Size alone does not decide strength. A small neodymium magnet can lift far more than a large fridge magnet; the material matters.
Both forces can repel. Like charges and like poles push apart, while opposite charges and poles attract.
Turn off the current and a simple electromagnet loses nearly all its strength. The magnetic field comes from charge flowing in the coil.
Students often ignore spacing. Both electric and magnetic forces get weaker quickly as objects move farther apart.
A class records how many paper clips an electromagnet lifts: 10 turns lifts 5 clips, 20 turns lifts 10 clips, 30 turns lifts 15 clips. The battery and nail stay the same. What question does this data answer, and what would you predict for 40 turns?
Answer: The data shows that more turns make a stronger electromagnet; at 40 turns the prediction is about 20 clips.
Build electromagnets with a nail, insulated wire and a battery, and have each group change one factor: turns, number of batteries, or core material. Post every group's data so the class can ask questions across data sets. Warn students that coils get warm.
Assessment usually gives a table or graph and asks which question the data answers, which factor had the biggest effect, or what further question to ask. Practice turning vague wonderings into testable questions with one clear variable.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: C) Increasing the current in the coil
More current produces a stronger magnetic field around the coil, so the electromagnet lifts more.
Answer: B) How does the distance between two charged balloons affect how strongly they repel?
A testable question names a variable to change (distance) and a result to measure (strength of repulsion).
Answer: 12 (also accepted: 12 clips)
24 turns is 3 times 8 turns, so expect 3 times as many clips: 4 × 3 = 12.
Answer: D) It gets weaker
Electric forces weaken as distance increases.
Answer: C) They repel
Like poles repel and opposite poles attract.
Answer: paper clips lifted (also accepted: number of paper clips, paper clips, clips lifted, clips)
The number of clips lifted is what is measured, so it is the dependent variable. The number of turns is changed on purpose.
Make observations to provide evidence that energy can be transferred from place to place by sound, light, heat, and electric currents.
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.
A full lesson with slides, activities and an exit ticket on electric and magnetic force strength, pitched to grades 6-8 and editable in PowerPoint or Google Slides.
Make a lesson →A printable, differentiated worksheet on MS-PS2-3 with an answer key, ready in about a minute.
Make a worksheet →Turn electric and magnetic force strength into a quiz students answer online that marks itself, with a class summary for you.
Build a test →Electromagnets, electric motors and generators are the main examples, because their strength or speed depends on current, coil turns and magnet strength.
No. Quantitative questions are limited to proportional reasoning and simple algebraic thinking, such as predicting from a doubling pattern.