Why is thunder noise

The lightning flash heats the air around it so quickly that the air expands very fast. When you heat something, it gets bigger — it expands. The air around the lightning flash expands so fast that it makes a shock wave in the air. That shock wave is the thunder that you hear. Why is thunder so loud? The louder the sound that you hear, the closer you are to the lightning. Light travels through air much faster than sound. If you see the lightning and hear the thunder immediately, then the lightning is very close to you.

Read more: Some truths about lightning: when thunder roars, go indoors. So, remember this important lesson: when thunder roars, go indoors. Hello, curious kids! Ask an adult to send your question to africa-curiouskids theconversation. Please tell us your name, age, and which city you live in.

Portsmouth Climate Festival — Portsmouth, Portsmouth. Although a lightning discharge usually strikes just one spot on the ground, it travels many miles through the air. When you listen to thunder, you'll first hear the thunder created by that portion of the lightning channel that is nearest you.

As you continue to listen, you'll hear the sound created from the portions of the channel farther and farther away.

Typically, a sharp crack or click will indicate that the lightning channel passed nearby. If the thunder sounds more like a rumble, the lightning was at least several miles away. The loud boom that you sometimes hear is created by the main lightning channel as it reaches the ground. Since you see lightning immediately and it takes the sound of thunder about 5 seconds to travel a mile, you can calculate the distance between you and the lightning.

Much is written about lightning — why it occurs, its potential for danger and how to avoid it. Yet we rarely hear or read about an electrical storm's audio accompaniment: thunder. Because thunder comes from lightning strikes, however, we'll first cover a few facts about those "bolts from the blue. To begin with, note that lightning bolts have no curves along their paths. All sections of a zigzagging bolt are straight and they connect at sharp angles.

During thunderstorms, lightning bolts may occur inside a cloud, between a cloud and the earth's surface, between two clouds, or even between a cloud and the surrounding air. Within storm clouds, moisture, warm and cold temperatures and fast moving air all combine to create a strong electric charge. Once that charge builds to several million volts enough to cause the electrical breakdown of air , those megavolts force a tremendous electric current to flow to or from a region with an opposing charge.

The path of this current can be many miles long, but it is no wider than a garden hose. The flow of current instantly heats surrounding air to an extremely high temperature. The gaseous expansion caused by that incredible heat then collapses, creating cylindrical shock waves along the entire bolt path.

These waves are transmitted initially as one clap of thunder. So, now we know what causes thunder. But here's the mystery: The shock waves that cause thunder last only a fraction of a second, so why does the booming carry on for up to several seconds?

Echoes off ground surfaces, buildings and nearby mountains are one reason, but the main factor behind thunder's longevity is the extreme length of the lightning bolt. Lightning races through the sky at more than 60, miles per second, but sound travels through air at only one-fifth of a mile per second. So, if a long vertical flash is one mile away, the first thunder arrives in five seconds.

The sounds continues to arrive from higher and higher up the bolt, and may last several seconds or more. In similar fashion, the speed of sound is also partly responsible for the rumbling we hear, due to refraction — the bending of sound waves.