Monday

Rain keeps the crew inside, so the Field moves to the kitchen table. Raven holds a small fridge magnet above a sheet of paper.

Under the paper lie three paper clips. She lowers the magnet. The clips jump up and cling to the paper from below.

"It never touched them," Rocket says. "The paper is in the way, and they still moved."

Raven lifts the sheet with the clips hanging under it. "What do you notice? The pull went right through."

Nova hovers low, lighting the clips. "Every force you measured so far needed a touch," she says. "This one does not."

Rocket is already peeling a strip of clear tape off the table. "I know another one," he says. "Watch this."

The tape swings toward his hand before he gets close. Nova hums. "Two forces without touching. Welcome to week 10."

Until now, every force at the Field came from a touch: a push, a pull, a bump, a rub. Magnets and charged objects are different.

A physics text calls this action at a distance: a force between objects too far apart for their atoms to touch.

All magnets attract iron, such as the iron in a refrigerator door. Magnets may attract or repel other magnets.

Rubbing things together can give them electric charge. A charged comb attracts neutral bits of paper from a distance.

Scientists say these forces can be attractive or repulsive. Attract means pull toward. Repel means push away.

Experiments show that all magnets have two poles. If a magnet hangs freely, one pole points toward the north.

The two poles are named the north magnetic pole and the south magnetic pole.

It is a universal rule of magnets that like poles repel and unlike poles attract. North pushes north away. North pulls south in.

You cannot cut a magnet to get a lone north pole. Each piece has both a north and a south pole.

Good noticing. Tomorrow you learn why rubbing makes tape cling, and what charge has to do with it.