Why is there an interval between lightning and thunder?

The reason for this is that light travels faster than sound. The speed of light is 300,000 km per second. On the contrary, sound is slow and covers only about 330m in one second, i.e. one kilometer in 3 seconds. If we count the seconds till we hear the thunder after seeing the flash of lightening in the sky and divide this value by three, we will know how many kilometers the storm is away from us.