Today’s Wonder of the Day was inspired by phoebe from , AL. phoebe Wonders, “What makes thunder storms” Thanks for WONDERing with us, phoebe!

When you look up into the sky at an approaching storm, it may appear to be nothing more than a cloud. You may be surprised to learn there is a lot more going on inside than meets the eye.

The air inside a thundercloud is very cold because it is so high in the atmosphere. This causes some of the moisture in the cloud to freeze. As the tiny bits of ice are blown around, they bump into each other, creating an electrical charge.

This phenomenon is similar to static electricity. As the ice bits collide, positive charges called “protons" gather at the top of the cloud, while negative charges called “electrons" settle at the bottom.

On calm weather days, the sky typically has a neutral charge. This means protons and electrons are evenly dispersed. As the positive and negative charges begin to separate on stormy days, the weather starts to get a little wild.

Lightning is a case of opposites attracting. The negative charges in a cloud are attracted to the positive charge of Earth's surface. When the charges become strong enough, electricity flows from the negatively-charged cloud to the positively-charged surface of the Earth, creating a lightning bolt.

For a brief moment, the air inside a lightning bolt can become up to five times hotter than the surface of the Sun. A single lightning bolt can reach 50,000° F. This sudden, extreme heat causes an explosive expansion of the air and the result is a thunderclap.

Lightning travels at the speed of light: a whopping 186,000 miles per second. Sound waves travel very slowly in comparison, about one mile in five seconds. You can use this information to figure out how far away a storm is.

All you need is a simple mathematical equation. When you see lightning strike, begin counting the number of seconds between the lightning flash and the clap of thunder. Divide that number of seconds by five to figure out how many miles away the storm is.

A word of caution: Lightning and thunder are two of nature's great wonders. Although they can be mesmerizing and beautiful, storms can also be deadly. At times it may be tempting to head outside to get a better view, but the safest place to enjoy a thunderstorm is indoors.

During a thunderstorm, not only is the ground positively charged, so is everything on it. Whether it's a tree in a forest, a building in a city, or a person standing on a baseball diamond, the tallest object in an area runs the risk of being struck by lightning.

If you cannot get safely indoors during a storm, there are a few things to remember. Always avoid standing under or near the tallest trees or objects in an area. This includes light poles and flagpoles. Avoid metal objects, such as fences or bleachers. Do not stand near or take shelter under isolated objects, such as a single tree in the middle of an open field. Do not stand in pools of water or open fields.

At home, it is important to avoid using corded landline phones during a thunderstorm. If you need to make a call, use a cordless phone or cell phone. Do not use equipment connected to electricity, such as computers or stoves, during a storm. Stay out of the shower and avoid using plumbing until the storm has passed. Lightning has been known to travel through phone lines, electric lines, and plumbing lines.

Following these safety tips can make a thunderstorm a lot less scary and much safer, which means all that's left to do is enjoy the show!

Wonder What's Next?

Who left the lights on? Mother Nature did. Tomorrow in Wonderopolis, we will meet a little bug with big glowing power.