How Does the Humidity affect the rate of Condensation of a Material?
Category: Earth Science—Meteorology
Project Idea by: Jared Cathey
Temperature is a measure of how hot or cold a material is. The greater the temperature, the hotter the material. As the temperature increases, the motion of the particles in the material increase. As the temperature of a liquid increases, the speed of the liquid particles increases. As particle speed increases, the particles move farther and farther apart until finally they separate and are in a gas state. So an increase in temperature increases the evaporation rate of a liquid.
As the temperature of gas particles decreases, the speed of the particles decreases, causing condensation (the change from a gas to a liquid). The particles move closer together until they are in a liquid state. So a decrease in temperature increases the condensation rate of a gas, which is the amount of gas that condenses in a certain amount of time.
When warm, fast-moving particles of water vapor in the air collide with a cool surface, they lose some of their heat, which results in their moving at a slower speed. The cooler, slower-moving particles of gas form liquid water particles. For example, the cold outside surface of a soda can often has drops of water on it due to condensation of water vapor in the air.
On some days, the cold surfaces of cans or glasses are covered with more water than on other days. Humidity is the measure of the amount of water vapor in air. Does the amount of water that condenses on a surface depend on humidity? A project question might be, "What effect does humidity have on condensation rate?"
Clues for Your Investigation
Design a way to measure the rate of condensation on a material; for example, the time it takes for enough moisture to collect and form a drop that will roll down the side of a vertical surface. The experiment can be done on days of different humidity or in containers that have different humidities. A closed container with an open bowl of water in it will have a higher humidity than one without the water and an even higher humidity than one with a drying agent such as borax.
Independent Variable: Humidity
Dependent Variable: Rate of condensation
Controlled Variables: Testing containers, cooling procedure of containers, timing procedure
Control: Test with medium humidity (container without an open bowl of water or drying material in it)
Other Questions to Explore
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