Period+1+Group+2

Response to Investigation 6 Essential Question(s)**
 * Period 1 Group 2

=We can determine that water vapor is in the air by doing a lab with ice and a cup and it gets there by evaporation. We learned this by doing a lab in class where we made a surface reach dew point. Water vapor is always in the air. It gets there by a slow process called evaporation. This is when the sun or another heat source gives heat energy to liquid water. The molecules in the water gain molecular motion and eventually turn into a gas called water vapor from the heat. We can positively determine that water vapor is in the air by getting a glass of colored ice water and watching water vapor in the air around it condense onto the side of the cup. We know that the water on the cup isn't leaking from the inside of it because it's not colored like the ice water. What happens is the colder temperature surrounding the cup drops the temperature of the air around it to dew point and the water vapor in that air sticks to a colder surface- the cup.= =Humidity is the amount of water vapor in the air and is measured in percentage. I know this from Investigation 1 when we had the hygrometer that measured humidity. It was in percent the measurement when we went outside to measure weather factors with tools. The amount of water vapor in the air determines how humid it is. When there is a lot of water vapor in the air, the air is very humid. When there is less water vapor in the air, the air is not as humid.= =Dew point is the temperature at which air becomes saturated and the extra water vapor in that air begins the process of condensation. It is measured in degrees Celsius. I know this from when we read the "Dragon’s Breath" article which explains all about dew point. This term is very important to know when dealing with weather since clouds and dew are based on it. Dew point isn't always the same everywhere because different places have different amounts of water vapor in the air. Warmer air can absorb more water vapor and colder air can hold less water vapor. If humidity increases and the temperature stays the same, then the relative humidity increases and the air might even reach dew point. If the temperature stays the same but the humidity decreases then the relative humidity decreases, pushing the temperature of the air farther away from dew point.= =Dew and clouds are formed when the temperature of the air drops to dew point and the water vapor in that air condenses onto a colder surface(s) and condensation nuclei. We learned this by reading the "Dragon's Breath" article and doing the cloud in a bottle lab. Dew forms when there is water vapor in the air around an object outside. Usually dew forms over night. What happens in that period of time is the temperature of the air outside drops to a temperature where it becomes saturated. This means that the excess water vapor in the saturated air needs a place to go, so it condenses onto a colder surface. That is why you see and feel moisture on things outside in the morning like grass, car windows, etc. Clouds are much different since they happen in the atmosphere. Atmospheric pressure decreases more and more as you increase in elevation. That means that it gets much colder. In order for clouds to actually form though, the temperature of the air at that elevation needs to reach dew point which is explained above. If and when this happens, the excess water vapor in that air needs a place to go. It condenses onto little pieces of dust or something along the lines of that, and those little pieces are called condensation nuclei. After this takes place then the rest of the water vapor just condenses onto the other water molecules that previously condensed onto the condensation nuclei, making a cloud eventually. The more water vapor that condenses the bigger the cloud.=
 * 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?**