Period+3+Group+2

Response to Investigation 6 Essential Question(s)**
 * Period 3 Group 2

We can determine that water vapor is in the air by causing it to condense on a cooler surface. We know this because we did a water in the air lab and analyzed how water vapor condenses on surfaces. We learned that when there is a cool surface surrounded by warmer air the air transfers its energy to the cool surface. The air then loses molecular motion and the water vapor in the air cools and changes from a gas to a liquid, this is called condensation.

Water vapor gets into the air by the process called evaporation. We learned this when we analyzed our evaporation lab. When a warm energy source, such as the sun, transfers energy to cooler bodies of water, the liquid water gains molecular motion. Once it gains enough energy it will turn into a gas called water vapor and evaporate into the air.

Humidity is the amount of water vapor in the air, and dew point is the temperature at which the air is saturated at a specific temperature. When we read the "Dragon's Breath" article, and our study guides, we learned humidity is measured in a percentage by a hygrometer comparing the amount of water vapor in the air and the amount needed to saturate it, otherwise known as relative humidity. You can measure humidity by using a wet-and-dry bulb thermometer. Dew point is measured in degrees Celsius. To find the dewpoint, you can repeatedly cool a liquid and check the temperature when condensation forms on the surface the liquid is in

Clouds and dew form when the air reaches dew point, or saturation (of water vapor), and the water vapor vapor condenses on a cooler surface than its own, such as condensation nuclei that are in the air. We learned in the "Observing Clouds" and "Dragon's Breath" articles, that the sun gives energy, or molecular motion to the Earth's water. The water gains enough energy to turn into its gas form, called water vapor, and evaporate. The water vapor rises into the atmosphere because it is less dense than the surrounding air until it cools due to the high elevation. The air molecules contracts and saturates to dewpoint. The air then can not hold the water vapor so the water vapor condenses on little particles called condensation nuclei. When billions of these water molecules join together, they form a cloud.