Science Fair Topics: Evaporation

Describe what you understand by ‘independent variable’ and ‘dependent variable’ in a scientific study? ( 5 points) An independent variable is something you have control over, what you can choose and manipulate. It is a variable that stands alone and doesn’t change by other variables. Although in some cases, you may not be able to manipulate the independent variable. It could be already there and or fixed. A dependent variable is the variable that’s being tested in an experiment. If the experimenter changes the independent variable, the change in the dependent variable is observed and recorded. For example a scientist is testing the effect of light and dark on the behavior of moths by turning a light on and off. The independent variable is the amount of light and the moth’s reaction is dependent variable. A change in the independent variable (amount of light) directly causes a change in the dependent variable (moth

In this case, the independent variable is the gender and the dependent variable is the

1. For this experiment, what were the independent variable and the dependent variable? What were the constants?

The independent variable for the experiment was the paper towels. The dependent variable was the absorbency and strength. The constants for the experiment were the size of the paper towels that were used, the amount of water, the size of the beaker, the size of the cylinder and the amount of the weight.

Definition of rate of evaporation. How it changes as temperature changes. Therate of evaporationcan be defined as the number of water molecules that change phase from liquid to gas each second. The rate of evaporation is mainly set by the temperature of the liquid water.The higher the temperature of the liquid water, the faster the rate of evaporation. Definition of rate of condensation. How it changes as vapor pressure (a measure the amount of the gas water vapor above the liquid surface) changes. Therate of condensationcan be defined as the number of water vapor molecules that change phase from gas to liquid each second. The rate of condensation depends mainly on the vapor pressure in the space above the liquid surface. Thus, the higher the concentration of water vapor molecules above the liquid surface, the faster the rate of condensation. What is meant by saturation Why will a closed system like this always move toward saturation with respect to water vapor You may take saturation to mean the capacity or maximum amount of water vapor that will can exist in the air at a particular temperature. It is important to understand that saturation vapor pressure (or the maximum amount of water vapor that can be in the air) increases exponentially as temperature

A dependent variable is the outcome or affected concept or characteristic from the independent variable.

A dependent and the independent variable of psychology are different. Independent variable means the variable experiment changed, while dependent variable means variable experiment measure, after making the change. For example, the time and ten random word pairs are independent variables because they do not change.

1 What is the ONE independent variable in this study? What are the dependent variables?

b. Independent variable-The treatment or experimental variable manipulated by the researcher to create an effect on the dependent variable.

Evaporation often implicitly includes transpiration from plants, though together they are specifically referred to as evapotranspiration. Total annual evapotranspiration amounts to approximately 505,000 km³ of water, 434,000 km³ of which evaporates from the oceans.[5]

The dependent variable refers to the status of the 'effect '(or outcome) in which the researcher is interested; the independent variable refers to the status of the presumed 'cause, ' changes in which lead to changes in the status of the dependent variable…any event or condition can be conceptualized as either an independent or a dependent variable. (Rosenthal & Rosnow, 1991).

Independent variable and subject variables are similar in the fact that both types of variables can impact the results of a test. Both independent and subject variables can be used to assess relationships between two items (Kiess & Green, 2010, p. 10-12). The difference arises in the control the experimenter has: near complete when dealing with independent variables, and very limited when working with subject variables (Kiess & Green, 2010, p. 10-12). For instance, a researcher can alter the amount of light in a room for a vision test, but cannot control if the subject has limited eyesight ability due to a congenital disorder.

Evaporation, in general, involves a substance changing its physical state from a liquid to a gas (US Department of Commerce, n.d; National Geographic Society, 2013; Northwest River Forecast Centre [NRFC], n.d). An example of this is when the body heats up during exercise or due to temperature, and releases sweat to try and cool down and producing water onto the skin (US Department of Commerce, n.d). Energy is required for evaporation to occur, and this energy source can come from the atmosphere, entities such humans, or in the case of the water cycle, the sun is the source of energy (US Department of Commerce, n.d). During the hydrologic cycle, evaporation occurs when the sun interacts with liquid water such has lakes and rivers, the ocean and soil, to cause water particles to become water vapour by heating the water (National Geographic Society, n.d; Miller & Spoolman,

Independent variable ( IV ), it is factor that has been influencing the dependent variable. This type of variable can change the independent of other variables. For this study, the assumption for independent variables are a.) Psychological factors b.) Marketing Mix

The change in the rate of evaporation by surface area is evident for all eyes in the proceeding experiments later in this report. The effect that surface area has on evaporation can be explained using the example from the understanding concepts question #1 on page 535.