What is the sound of thunder mean?

The sound of thunder is the result of the rapid expansion and contraction of air surrounding a lightning bolt. When lightning strikes, it heats the air to extremely high temperatures, causing it to expand explosively and create a shockwave. This shockwave travels through the air as sound waves, producing the rumbling or cracking noise we associate with thunder. The intensity and duration of the sound can vary based on factors like distance from the lightning and atmospheric conditions.