Zippers, Pulleys, and Giant Seeds: Simple Wonders of Our World

What Is a Pulley?

A pulley is one of the oldest and simplest machines made by humans. It helps lift heavy things by using a rope and a wheel. The idea goes all the way back to Archimedes in the third century BCE. The rope runs through the middle of the wheel, which makes it easier to lift or carry heavy objects. The more wheels you use, the easier it becomes. Also, pulleys make it possible to pull down on the rope to lift something up, which is much easier than trying to push it up yourself.

Who Invented the Zipper?

The first idea for a zipper was written down in 1851, but it wasn't actually built. Over 40 years later, an American named Whitcomb Judson made a zipper for shoes, but it didn’t work well because it used tiny hooks instead of the teeth we know today. Around 20 years after that, in 1917, a Swedish-American engineer named Gideon Sundback created the modern zipper. His version worked well and became a big hit. Soon, zippers were used in clothes, bags, blankets, and many other things.

What Is the Largest Seed in the World?

The biggest seed in the world comes from the Coco de Mer palm tree. One of its seeds can weigh up to 18 kilograms! These huge seeds are often found on faraway islands. That’s because they float on ocean waves and travel long distances. Sometimes, they reach a quiet island, take root, and begin to grow.