At what temperature does dew form?

Question

I have a worksheet where it gives u the name of a city the high temperature and the low temperature. it also gives you relative humidity at the high temperature and unsaturation(percentage of water vapor that could be added. it asks me to put a check mark next to each city where dew would form at night.

For example,

City: New Orleans
High: 33 degrees Celcius
Low: 23 degrees Celcius
Temperature range: 10 degrees
Relative humidity at high: 95%
Unsaturation: 5%

Would I check this city? Please explain why or why not.

Answer 1

The temperature at which the relative humidity becomes 100 percent.

Answer 2

You may be missing some information. There is either an equation needed (which maybe you are supposed to know as part of the exercise you are working on) or there should be a dewpoint chart published with your textbook or workbook. As an alternative, you may be able to find a dewpoint chart on the net. There is no set temperature at which dew forms. It depends on the humidity of the air, how much the air cools. This causes fog or drizzle or ice crystals in the air, depending on other ambient factors. Another factor -- dew can form on surfaces even when the air temperature does not fall to the dew point. How? Due to radiative cooling of a surface (loss of energy to space) the surface may be cooler than the dewpoint temperature and thus develop dew. I suspect the question you are working on is simply asking for whether or not dew will form in the air (as fog, cloud, drizzle) given the parameters of the question. Your dewpoint chart or appropriate calculations will provide the answer. Hope this helps without telling you more than you need to know.

Answer 3

The temperature that dew forms depends on what the humidity is. The dew point is the temperature that water vapor starts condensing out and is dependent on how much water vapor is in the air. If the air is dry, the dew point is low. If the air is saturated, the dew point is near the current temp.

There is a dew point chart that tells at what temp the water will condense, depending on the saturation.New Orleans is humid, 95% As it gets cooler you will reach the dew point quickly.

Answer 4

Condensation forms on the outside of the cup when moisture which is naturally present in the air cools down, similar to the effect on clouds when they cross mountainous regions. As the cloud rises it cools down and the vapour begins to condense forming droplets of water or crystals of ice. The reason why it does not form on any object which are at room temperature is because air at certain temperatures can hold different amounts of moisture for example in a jungle where it is hot and wet you will find it is very humid because the air can hold more vapour when warmer. The reason why you do not get condensation on anything else in the room is because the moisture content of the air is not high enough to reach saturation at that temperature.