Circuit Builder Lab

The light in the farm shed had stopped working, and Little Thunder was not happy about it.

"I can't find my hat in the dark," he grumbled.

Spike pulled a box off the shelf. Inside was a science kit: a small battery, wires with clips, a tiny globe, a switch and a buzzer. "Let's learn how circuits work. Then we'll know what's wrong."

They spread everything on the workbench. Suzy clipped one wire to the battery and the other to the globe. Nothing happened.

"A circuit has to be a complete loop," Spike explained. "Electricity flows out of the battery, through the globe and back again. If there's a gap, it stops."

Suzy connected the second wire. The little globe glowed!

"Magic!" said Little Thunder.

"Science," corrected Spike, grinning.

Next they tested materials by putting them in the gap. A metal spoon made the globe light. A nail did too. But a wooden peg, a rubber band and a feather did nothing at all.

"Metals are conductors," said Suzy. "They let electricity through. Wood and rubber are insulators. They block it."

"That's why wires have plastic around them," Spike added. "It keeps the electricity safely inside."

Little Thunder added the switch. Click, on. Click, off. Then he swapped the globe for the buzzer, and it gave such a loud BZZZT that he jumped and knocked over a bucket.

They tried two globes in a row, called series, and both glowed dimly. Then they gave each globe its own path, called parallel, and both shone brightly.

"So what's wrong with the real shed light?" asked Little Thunder.

Spike shook his head. "Real electricity is dangerous. We never touch it. We tell a grown-up."

So they did. That afternoon an electrician found a broken wire in the wall, a gap in the loop, and fixed it.

The light flickered on. There, on the hook, was Little Thunder's hat.

"Complete circuit," he said happily, "complete Thunder."