My seven year old son wanted to know this morning as we drove to his school on an uncharacteristically frosty morning, for this time of year. We get very heavy frost in winter but not normally in autumn. It wasn't cold this morning either. But I found I couldn't really answer his question of what it is and what causes it. Simple explanations are specifically what I am looking for.
2007-03-18 13:58:00 · 5 answers · asked by T 3 in Science & Mathematics ➔ Weather
Frost forms in much the same way as dew. Frost forms when a surface cools (through loss of infrared radiation) to a temperature which is colder than the dewpoint of the air next to the surface. Frost is frozen water that has condensed from some of the water vapor contained in the air. If a significant layer of air next to the ground were actually cooling to the dewpoint, then a visible shallow layer of fog would form. Instead, the air next to the surface (say grass) must be so thin that the only evidence that condensation has occurred is the frozen water on the grass.
Interesting facts:
HOAR FROST: Huge ice crystals of frost can develop if a cold surface (typically well below 32 degree f) is exposed for a long period of time to humid air. This can happen on the underside of ice covering if the river level has fallen since the ice was formed, leaving a humid layer of air trapped between the surface of the river and the underside of the ice. Hoar frost is also found in some layered snowpacks.
2007-03-18 14:02:00 · answer #1 · answered by Anonymous · 0⤊ 0⤋
Cold makes frost!
2007-03-18 21:21:44 · answer #2 · answered by rico3151 6 · 0⤊ 0⤋
A guy named Jack makes Frost...Jack Frost.
2007-03-20 23:34:36 · answer #3 · answered by Anonymous · 0⤊ 0⤋
condensation in low temperatures....for a 7 year old, wet air that gets so cold it has to lay down for a while- at least until the sun comes out
2007-03-18 21:07:05 · answer #4 · answered by ? 5 · 0⤊ 0⤋
condensation and dew
2007-03-19 06:26:04 · answer #5 · answered by Justin 6 · 0⤊ 0⤋