The speed of sound<span> is greater in hot </span>air<span> than it is in </span>cold air<span>. This is because the molecules of </span>air<span> are moving faster and the vibrations of the </span>sound<span> wave can therefore be transmitted faster. This means that when </span>sound travels<span> from hot </span>air<span> to </span>cold air<span> or from </span>cold air<span> to hot </span>air<span> it will refract.</span>
