How do builders dig a tunnel from both ends and meet in the middle?

What Crafty Clover says in this video

Intro

Hi there, curious minds! I'm Crafty Clover! Let's discover something amazing. How do builders dig a tunnel from both ends and meet in the middle?

The Big Idea

Imagine two crews digging toward each other underground. They cannot see each other! Yet they meet right in the middle.

Measure

Step one: Measure. Surveyors measure everything very carefully. They use lasers and satellites to mark the tunnel's exact path.

Dig Both Ways

Step two: Dig Both Ways. Crews can then start digging from two sides, aiming at the same point. Computers check the direction all along.

Meet Up

Step three: Meet Up. The Channel Tunnel between England and France was dug from both ends. The two tunnels met with an error of only about one foot.

A Closer Look

Let's take a closer look! Satellites mark points above. Lasers guide the digging. Gyroscopes help underground. Computers check the path.

Quick Facts

Quick facts! Surveyors also use gyroscopes underground, where satellite signals do not reach. The Channel Tunnel goes under the sea between England and France. Workers cheered when the two sides met. Being only about one foot off after many miles is amazing.

Think Like a Scientist

Now, think like a scientist! Have a friend start at one end of a hallway. You start at the other end. Walk slowly toward the middle and stop at a mark. Use a ruler to see how close you met. How could you aim better?

Outro

Builders dig a tunnel from both ends and meet in the middle by measuring very carefully with lasers, satellites, and gyroscopes, while computers check the direction all along. Science is amazing! Keep asking questions! The more you look around, the more wonders you will find, so keep your eyes open! Crafty Clover can be found on Amazon Books, Google Bookstore, and Apple Books. Available for purchase or download! Bye for now!