Electricity and magnetism are the unit where my students keep asking the best question in science: how can one thing push or pull another thing without ever touching it? A magnet drags a paperclip across the desk with a visible gap between them. A balloon rubbed on a sweater lifts a kid hair right off their head. Nothing reaches out and grabs anything, and yet a force is plainly at work.
The trick is to teach electricity and magnetism as two halves of one idea instead of two separate units. Both are non-contact forces, both work through fields, and the moment you send electric current through a coil of wire you get a magnet you can switch on and off. Here is the order I teach it in for MS-PS2-3 and MS-PS2-5.
What is the difference between electric and magnetic forces?
Electric forces act between charged objects, while magnetic forces act between magnets and magnetic materials such as iron. Both can attract or repel: with charges, like charges repel and opposite charges attract; with magnets, like poles repel and opposite poles attract. They are different forces with different sources, but they follow the same attract-or-repel pattern, which is why students confuse them.
- Electric force: acts between charged objects; like charges (two positives or two negatives) repel, and opposite charges attract.
- Magnetic force: acts between magnets and magnetic materials; like poles (north-north or south-south) repel, and opposite poles attract.
- Shared pattern: both forces can either pull objects together or push them apart, depending on what is facing what.
How do I teach that these are non-contact forces?
Electric and magnetic forces act at a distance, meaning objects push or pull on each other without touching. I prove it with a gap: a magnet that drags a paperclip across the desk before they meet, or two magnets that repel hard enough you can feel the resistance through empty air. The visible space between the objects is the whole point, so I never let it disappear.
Slide two bar magnets toward each other on a smooth desk, like poles facing, and let students feel the invisible push grow before the magnets ever touch. Then do it with a charged balloon lifting a stream of water or a scrap of paper. That stubborn gap is what tells students a force can reach across empty space, and it sets up the idea that fills the next section.
What is a field, and how do I make it visible? (MS-PS2-5)
A field is the region around an object where its force can be felt, and it gets weaker the farther away you go. Fields explain how non-contact forces work: the magnet does not need to touch the paperclip because its magnetic field already fills the space around it. MS-PS2-5 asks students to investigate evidence that fields exist between objects that are not in contact.
Iron filings sprinkled around a magnet snap into the loop-shaped pattern of its field, and a compass needle swings as you walk it around the magnet, mapping the same shape point by point. Move the compass farther away and the pull weakens, which shows the field thinning with distance. Collecting that kind of evidence that the field is really there, in the gap, is exactly the investigation MS-PS2-5 is after.
What is an electromagnet and how do I build one with students? (MS-PS2-3)
An electromagnet is a magnet you make by running electric current through a coil of wire, often wound around an iron nail. The moving charge produces a magnetic field, so the coil acts like a magnet, and cutting the current switches it off. Students can build one with a battery, wire, and a nail, then pick up paperclips to prove the magnetism is real.
Wrap insulated wire around an iron nail, touch the ends to a battery, and the nail suddenly grabs paperclips; lift the wire off the battery and they all drop. That on-off switch is the moment electricity and magnetism become one idea, because the magnetism only appears while charge is moving through the coil. It also hands students a setup they can change and measure, which is what the next section is built on.
How do I get students asking questions about what affects force strength? (MS-PS2-3)
MS-PS2-3 asks students to ask questions about data to determine what affects the strength of electric and magnetic forces. The electromagnet is perfect for this: students can change the number of coils or the amount of current, count how many paperclips it lifts, and use that data to figure out which factors make the force stronger or weaker.
- More coils: add turns of wire around the nail and record whether it lifts more paperclips, then graph coils against paperclips lifted.
- More current: compare one battery to two and see how the count changes, while keeping everything else the same.
- Ask and test: have students pose their own questions, such as whether a thicker nail or a longer wire matters, and use the paperclip data to answer them, which is the heart of MS-PS2-3.
Teach it as one connected story, non-contact forces that work through fields, with electricity and magnetism joined the instant current flows through a coil, and MS-PS2-3 and MS-PS2-5 stop being separate standards and become a single idea students can build, test, and explain.