Period+1+Group+7

Response to Investigation 6 Essential Question(s)**
 * Period 1 Group 7

=We can determine that water vapor is in the air by seeing the result of condensation on our windows. We know that there is water vapor in the air by doing an experiment in class. The experiment involved a cup, ice, and an additional cup.The materials we used was a cup of room temperature water and a cup of ice. We put the cup of ice in the cup filled with water. After a few minutes, the cup started forming little drops of water called condensation or dew. The drops formed because of heat transfer. For example, the sun or sol gives its energy to water from rays. The water on the Earth gains molecular motion and the water evaporates. The evaporated water goes into the air and that is called water vapor. Humidity is the amount of water vapor in the air. It is measured in percent by a hygrometer or a radiosonde. We learned about humidity in Investigation 1, when our class traveled outside to measure humidity with a hygrometer. When the air is warmer, it can hold more water vapor. This is because the molecules in the air will spread out leaving there more space for water vapor to fill the air. The colder the air, the less water vapor it can hold. This is because the air molecules are more compact, and there is less room for water vapor. 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, and it evaporated into the air. 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. Dew point is not the same everywhere. It depends on the amount of water vapor in the air. The lower the temperature, the more water vapor is in the air. Also, you can see your breath, only if dew point is reached. Clouds form when the dew point and the temperature meet in the atmosphere. Pressure is then added, which makes the temperature rise. The air is then saturated, then the pressure is released which makes the temperature drop. The water vapor in the air condenses onto condensation nuclei, a surface where water vapor condenses onto in the atmosphere. I know this because of our bottle demonstration when we added water and shook it to make the water warmer so it would evaporate, and then added smoke to symbolize the condensation nuclei. Condensation nuclei can be molecules of dirt to pollen to dust. We then added pressure by squeezing the bottle. The pressure would make the volume of the bottle decrease, having the dew point being met and making the molecules inside the bottle closer together, making more collisions occur, and making the air warmer. Then, we decided to decrease the pressure by releasing the man-made force and the temperature dropped. Since colder air can hold less water vapor than warmer air, the evaporated air condensed onto the smoke, or condensation nuclei, and a miniature cloud formed. Dew is formed in a similar way. Dew forms by dew point being met with temperature in the atmosphere. The temperature would then drop, making extra water vapor in the air condense on the colder surface, which is the grass. We learned this in a class discussion while learning about clouds. When dew forms, the temperature coordinates with the dew point. The air is saturated and the temperature drops. Since colder air can hold less water vapor than warmer air, the water vapor condenses onto the colder surface, which is the grass.=
 * 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?**