Its to capture light or to focus. don't forget to like. :D
<span>To answer the question above, if the day sky is clear it collects radiation. If air is dry snow sublimates faster. If both cases overlap it disappears faster where ever coldest. Thank you for posting your question here. I hope my answer helps. </span>
Hmmm the only formula i know is v = d * t or volocity = distance * time
