What Factors Affect the Rate of Evaporation of Water?
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Hubert Galan and Zafira Smith
Our testable question for this experiment is what factors affect the rate of evaporation of water. This testable question regards the different factors, such as the temperature surrounding the water being evaporation, the temperature of the water being evaporated, the temperature of the air surrounding the water being evaporated, the humidity of the air surrounding the water being evaporated. In order to test our question we will use a bowl of water and expose the bowl and the water inside of it, which would begin at a temperature of 30 degrees celsius, to many different conditions, such as heat lamps, and fans. In doing so we will exposing our bowl of water and water itself to the variety of different factors that we can assume are capable of affecting the rate of evaporation of our water, and by testing the each of these factors we will be able to determine which ones are actually influential to the rate of evaporation of the water being tested.
Evaporation is when water changes form into gas. "Evaporation is the main pathway that water moves from the liquid back into the water cycle as water vapor,"(The Water Cycle: Evaporation). What this means is that gas or water vapor's main way back into the water cycle is through evaporation, which shows the significance of it. More important information on evaporation is that energy is needed for evaporation to occur. The use of energy in evaporation is that energy breaks the bonds that hold water molecules together and which keeps the water in it's liquid phase. Which is why water easily evaporates at a high temperature, because there is enough energy or heat needed to break those bonds. Evaporation is arguably the most important part of the water cycle. No evaporation would result in no rain, no rain equals no water for forest which provided the most essential gas for humans, oxygen. Overall without evaporation the effects would be destructive (Water and Global Change). What this shows is how important evaporation is in our world, and that without it we won't survive. For this reason my colleague and I are trying to answer the question what factors affect the rate of evaporation of water.
Water molecules are always moving, some molecules are hit by other molecules which cause them to gain speed. These molecules hitting each other cause the energy and the temperature to raise. Temperature is the average kinetic energy of the molecules. Slower moving molecules have a lower temperature(colder) while faster moving molecules have a higher temperature (hotter). The increasing temperature causes the water molecule bonds to break, which causes water molecules to turn into gas. The breaking of bonds of molecules is evaporation, it involves a change of state, from liquid to gas. The higher the temperature, the higher the rate of evaporation. When the temperature of water increases the water molecules gain more energy. When the water molecules' temperature rises the water molecules start to move faster and thus evaporate faster. Basically the higher the temperature the higher the rate of evaporation (Factors Affecting the Rate of Evaporation). This is the most notable factor that affects rates of evaporation. The way we will test this is by having two bowls of water. One bowl will be exposed to normal conditions, while the other bowl will be exposed to a heat lamp. After twenty-four hours we will compare the mass of both bowls, and see if they change. After this we will conclude based on the data we received.
Wind is the natural movement of air in any given direction. In order to test the effect of wind on the rate of evaporation of the bowl of water in our experiment we will use a fan and turn it onto the bowl of water being used. When evaporation occurs the water vapor from our bowl will be sitting just above the surface of the water in our bowl that has not yet been evaporated. When wind is added to the environment in which a body of water is in, the molecules of water vapor are rapidly moved from their resting position above the surface of the remaining water to the direction which the wind is facing. This rapid removal of molecules allows for rapid evaporation to occur because there is an increased amount space on the surface area of the remaining water which allow the water molecules to evaporate up. (How Does Wind Affect Evaporation?) This also means that with an increased speed of wind there will be an increased rate of evaporation, as the molecules sitting on the surface of a body of water will be removed and replaced and a quicker rate.
Humidity is that amount of water vapor in the surrounding atmosphere of a body of water, in our case the cup being used in our experiment. In order to test the effect that humidity has on water vapor in our experiment, we will put a lid over the the bowl of water we will be using for testing. Evaporation in an airtight container increases the amount of water vapor that is present in the air above the water in said container. When the amount of water vapor in the air above our water increases, there is more humidity because humidity is the amount of water in the surrounding atmosphere in a body of water. When humidity is high in the air, it is harder for water to evaporate, because the air is filled with water vapor. The air can not absorb an unlimited amount of water molecules, meaning that there will be a slower rate of evaporation. If the space that is located above the water becomes filled with water vapor, then a condensations happens to cause a balance. (Factors Affecting the Rate of Evaporation). Condensation which is the opposite process of evaporation, is when water vapor converts to liquid, meaning that the evaporation taking place in our experiment would be countered by the condensation already occurring to the vapor within our closed cup of water.
If wind affects the rate of evaporation then our water will evaporate faster because wind increases the evaporation rate of water through removing the water vapor particles that will be resting above the rest of our remaining water( that has not yet been evaporated), making room for new molecules to rest in the same place.
If humidity affects the rate of evaporation then our water will evaporate slower because when humidity is high, it becomes more difficult for water vapor molecules to enter their atmosphere, therefore leaving no space for more molecules and slowing the rate of evaporation of water.
If temperature affects the rate of evaporation then our water will evaporate faster because when water's temperature is increased the water molecules gain more energy, which causes the molecules to move faster, break bonds faster and thus evaporate faster.*we have three hypothesis because we are trying to accurately test our questions with multiple factors in order to answer our testable question
"The Water Cycle: Evaporation." Evaporation, The Water Cycle, from USGS Water-Science -----School. N.p., n.d. Web. 17 Nov. 2016.
"Factors Affecting the Rate of Evaporation." Factors Affecting the Rate of Evaporation. N.p., -----n.d. Web. 16 Nov. 2016.
"How Does Wind Affect Evaporation?" Bright Hub. N.p., 18 Mar. 2011. Web. 17 Nov. 2016.
"Intermediate-Level Science Projects." Intermediate-Level Science Projects: What Factors Most -----Affect Evaporation? N.p., n.d. Web. 17 Nov. 2016.
"Water and Global Change." RSS. N.p., n.d. Web. 17 Nov. 2016.
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