Period+7+Group+3

Response to Investigation 6 Essential Question(s)**
 * Period 7 Group 3

=Water vapor is in the air, it gets there through evaporation. We know this because we analyzed the "water in the air lab". From this we learned that to determine if there is water vapor in the air, we could conduct an experiment. The experiment we conducted consisted of us putting two cups, one with water and one with ice, and putting plastic wrap over the top of them to trap all of the vapor inside the cups; we also put green food coloring in the cups. Then the air around the cup with the ice in it started to lose molecular motion, slowing down enough to turn back into a liquid, and it then condensed onto the outside of the cup, proving there is water vapor in the air. Water vapor enters the air through evaporation. We know this because we then analyzed that "water in the air" lab. From that we learned that there are multiple ways that water vapor gets into the air. One way is when a human exhales, they are breathing out water vapor back into the air. Another way water vapor gets into the air is through evaporation at the Earth's surface. When the sun's rays shine down on the water source the water molecules gain molecular motion. When the water gains enough molecular motion it turns into a gas form which is called water vapor, so that's how water vapor gets into the air.=
 * How can we determine that water vapor is in the air and how does it get there? What is humidity and what is dew point and how are each measured? How do clouds and dew form?**

=Humidity is the amount of water vapor in the air, and it is measured by a hygrometer. We know this because we analyzed an "evaporation and humidity" lab. From this lab we learned that humidity is commonly referred to as relative humidity by meteorologists. Relative humidity is the amount of water vapor in the air compared to the amount of water vapor needed to saturate a volume of air at that specific temperature; humidity is measured as a percentage. We also learned that the amount of water vapor in the air varies according to the temperature. When the air temperature is hotter, the air molecules expand outward making more room for water vapor. Likewise, the colder the air temperature is, the less water vapor can be held in the air because colder air molecules contract. So when the air temperature is cold, there does not need to be a lot of water vapor in the air for it to be very humid out. When the air temperature is hotter, there will need to be much more water vapor in the air for it to be very humid out.= = = =Dew point is the temperature at which water vapor turns back to a liquid and the air becomes saturated. We know this because we did a condensation and dew point lab. In this lab we saw that at a certain temperature the air became saturated and couldn't hold any more water vapor. We also did a Weather Balloon simulation. In this simulation we analyzed that the higher the weather balloon elevated the lower the dew point got and a certain dew point the balloon popped. Dew point is measured by a thermometer. The thermometer shows you at which temperature is saturated and cannot hold any more water vapor. This is how water vapor turns back to a liquid. The air being saturated condenses its water vapor to condensation nuclei to create precipitation.= = = =Clouds are formed when the sun heats the earth, when evaporation happens, and when condensation happens. We know this because we analyzed a lab called "clouds and precipitation". The sun's heat will cause more molecular motion to occur in water. Then the water will evaporate and rise higher up into the atmosphere. When that happens, the temperature will become lower because the temperature higher up in elevation is cooler. Then the vapor molecules will reach dew point and condense onto condensation nuclei. The condensation nuclei can be smoke or pollution and salt. The condensation nuclei that have condensed water vapor will come together to form a cloud. There has to be millions of condensation nuclei that form together, but when that happens, a cloud is formed. Also, dew is formed when there is water vapor in the air and a surface outside such as grass becomes cold. I know this because in class we did a lab called "what's in the air?" lab and we found out that water vapor condenses onto a cold surface. The water vapor in the air will change from a gas to a liquid or "condense" onto the grass because the vapor would have reached dew point, and the vapor would form as dew.=