The Thread That Glowed

Part One · Who Made It?

You flip a switch, and the room fills with light. Who made the light bulb?

Thomas Edison is the name most people know. But he did not make the very first bulb.

Other people made bulbs before he was born. Their bulbs burned out in a few minutes.

Edison made the first bulb that was practical. It lasted for hours and hours.

Edison's mom taught him at home. He learned by reading and trying things.

He had a small lab in his cellar. Later he built a bigger lab in Menlo Park.

Part Two · The Search

Edison did not work alone. He called his helpers muckers. He picked teams of them to build each new thing.

A bulb needs a thin thread that glows inside it. That thread is called a filament.

One helper tried thousands of things for the filament. He tried platinum and rubber. He even tried soot from lamps.

Then the team tried a cotton thread. They baked it until it was black and hard. They sealed it in glass with the air pumped out.

The thread glowed! It glowed for at least thirteen hours. The team had a bulb that lasted.

Part Three · The Whole Idea

Later a helper found something better. It was bamboo from Japan. A bamboo thread glowed for a very long time.

A bulb is not enough. The team also made switches, meters, and wires. Without a wire, the bulb could not glow.

In 1882, a power station sent light down wires. It lit just a small part of New York. Many years later, half of all homes had electricity.

Look at a light bulb at home. Do not touch it, because it can be hot. Can you see a tiny thread inside?

That thread is a filament. What do you think the team said when it glowed?