Thunder is usually heard some seconds after lightning is observed because
Answer Details
Thunder is usually heard some seconds after lightning is observed because light travels faster than sound. When lightning occurs, it produces a sudden burst of light which travels at the speed of light, about 300,000 kilometers per second. On the other hand, sound travels at a much slower speed, about 343 meters per second. As a result, the sound waves produced by the lightning take a longer time to reach our ears compared to the light waves. Therefore, we see the lightning before we hear the thunder, which is why there is usually a time delay between the two.