light arrives almost instantaneously at human scales. Even at a distance of 1 kilometer， This means light is approximately 874， sound speed varies significantly with the medium and temperature. In water。

sound is still hundreds of thousands of times slower than light. ， sound travels at about 1， while sound takes about 2.9 seconds—a delay easily perceptible to humans. This is why we use the time delay between lightning and thunder to estimate how far away a storm is: every 3 seconds of delay represents approximately 1 kilometer of distance. Interestingly，960 m/s. However， or observing fireworks explode before hearing the boom. For practical purposes， it can reach 5。

light arrives in just 3.3 microseconds，。

480 m/s (over 4 times faster than in air)， and in steel，030 times faster than sound. This enormous difference explains common phenomena like seeing lightning before hearing thunder， even at its fastest in common materials。