Period+7+Group+4

Response to Investigation 6 Essential Question(s)**
 * Period 7 Group 4

= = =We can determine that water vapor is in the air by an experiment /lab we did in class. We took a cup of ice water and left it on our desks. By observing it, we watched and saw water condense on the outside of our cup. The water vapor in the air condensed to the colder surface proving that there is water vapor in the air. Water vapor gets in our air by evaporation. When liquid water is heated up, it evaporates turning from a liquid to a gas. The water, therefore, is in the air just not in liquid form. I know this because of the demonstration in class we did when we dipped our fingers in water and made a circle with it on the top of our hand. Because our hand was a warmer surface, particles of the water’s molecular motion increased due to conduction, meaning more heat, evaporation and it went up inside the air. Humidity is the amount of water vapor in the air and is measured in percent. 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. Dew point is the temperature when saturated air turns back to a liquid. It is measured in degrees Celsius. I know this because of our Dragon’s Breath article that explains about relative humidity, dew point, etc. It states exactly what dew point is. Clouds form when water vapor in the air attaches onto a condensation nuclei, a surface where water vapor condenses in the atmosphere. Condensation nuclei can be anything from dirt to pollen to dust. Dew is formed in a similar war. Water vapor condenses to a colder surface such as grass. I know this because of our bottle demonstration where we saw it when you added ice.=
 * 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?**

We can determine that water vapor is in the air and how it get's there by doing an experiment. We know this from doing the "water in the air" experiment, and analyzing it by adding notes. In this lab, we made our group design our own experiment. My group had the two ziploc bags, one filled with food colored water, and the other filled with food colored water and ice. After a couple minutes, condensation began to form on the sides of the bag with ice and water. We knew it wasn't coming from the water in the bag because it wasn't the color from the food colored water. We then knew it was coming from the air. While analyzing, we figured out what was happening in the air. What happens is when the air get's cold enough, it contracts and in that area and cannot hold anymore water vapor than it already has. That's called saturated air. When the air is saturated it reaches dew point. When dew point happens water vapor in the air condenses onto colder surfaces. It condenses on colder surfaces because heat transfers from hot to cold. So our ice was cold enough that it condensed onto our bag of ice. That shows that their is water vapor in the air. We also learned other ways water vapor get's in the air so that we positively know it's in the air. First is terrestrial animals. When animals exhale, they are putting water vapor into the air. All the animals in the world doing that can put a lot of water vapor in the air. Also, from plants known as transpiration. Water enters the roots, and goes up the stem and comes out of the leaves, leaving as water vapor. Lastly, an energy source can change water into water vapor and it will rise into the air known as evaporation. Those three ways are the main ways to get water vapor into the air. So, that is how we can determine that there's water vapor in the air and it get's there.

Humidity is the amount of water vapor in the air. We learned this definition from the article that we read and talked to the text to called "Dragon's Breath". Humidity is measured in percent, and can change constantly. Warmer air expands; so when it's warmer out there's more room to hold water vapor in the air. Meaning that there is a higher percent of humidity. That's opposite is for cold air. Cold air contracts, so it can hold less water vapor in the air. Meaning a lower percent of humidity. Also, humidity is measured by a weather tool called the hygrometer. We learned this from our notes in Investigation 1. In that investigation, we learned about the weather tools and what each one measures. The hygrometer measures humidity, using a scale of numbers on the tool. Also, when the air at a specific temperature is holding its maximum amount of water vapor, it is called saturation. When the air is saturated, that temperature can be called dew point. We learned this from the article "Dragon's Breath". Dew point is measured in degrees celsius. Depending on the temperature, the amount of water vapor needed to saturate a mass of air is not always the same. For example, one kilogram of air holding 3.5 grams of water vapor, the 3.5 grams of water vapor will saturate the kilogram of air at 0 degrees Celsius. When the dew point is freezing, it will form frost instead of dew. What happens is it get's cold enough that the air saturates. Also known as dew point. Then the water vapor can start condensing onto other surfaces. So when dew forms, it's when the air is saturated and it condensed onto that area; hence, DEW point. So in that case, dew point is measured by a thermometer for taking the temperature. We learned this and the temperature at which definition from the article "Dragon's Breath". Dew point always is changing. So you can go out in the morning and take the temperature. If you look on charts that scientists have made showing how much water vapor is needed to saturate the air at that temperature, you can figure out if the air is saturated. Later on in the day, using your thermometer, (which takes temperature), if the temperature changes, so does the dew point. Because it will hold less or more water vapor depending on the temperature changing how much water vapors in the air, changing if the air is saturated or not. When the temperature drops below dew point, water condenses into crystal ice, frost, etc depending on the temperature of the air. To clear things up, for example, in the article, "Dragon's Breath," it showed that if 36 degrees Celsius air is holding 3.5 grams of water vapor, the relative humidity is 10%. this means that at 50% humidity, it can hold 7 grams of water vapor.

Clouds and dew form almost the same way but they are slightly different. Clouds form by the sun giving it's energy to the water source, making the water source gain molecular motion and evaporate into the air as water vapor. Then since heat rises, the molecules that were evaporated rise into the atmosphere. Once the molecules get higher they cool and start to condense. They condense onto condensation nuclei. Condensation nuclei is a small particle that is in the air like dust, salt, and smoke. Once it condenses on the condensation nuclei, it takes million of other condensation nuclei and starts to form a cloud. We learned how a clouds forms by reading "Observing Clouds." Forming a cloud can change in the process because sometimes, if condensation nuclei begin to form a cloud, and the temperature rises and the temperature will not be at dew point, water vapor could gain molecular motion and turn into a liquid. Dew forms similar to a cloud. We know how dew forms from a demonstration in a bottle. What we did was had room temperature water and the water gained molecular motion when we squeezed the bottle. By squeezing the bottle, we sped up the molecules, and we saw condensation form on the sides of the bottle. Condensation is basically the same thing as dew. But dew needs cold temperature to saturate the air. Once the air is saturated it condenses onto a colder surface. If you wake up in the morning and see dew on the grass now you know why. It's similar to a cloud though because clouds need that same process except they condense onto condensation nuclei. Also dew forms closer to the ground and clouds form higher in the sky.