Controlled Variable Definition

Controlled Variable Definition A controlled variable is one which the researcher holds constant (controls) during an experiment. It is also known as a constant variable or simply as a control. The control variable is not part of an experiment (not the independent or dependent variable), but it is important because it can have an effect on the results. It is not the same thing as a control group. Any given experiment has numerous control variables. Its important for a scientist to try to hold all variables constant except for the independent variable. If a control variable changes during an experiment, it may invalidate the correlation between the dependent and independent variable. When possible, control variables should be identified, measured, and recorded. Examples of Controlled Variables Temperature is a common  type of  controlled variable. If a temperature is held constant during an experiment it is controlled. Other examples of controlled variables could be the  amount of light, always using the same type of glassware, constant humidity, or duration of an experiment. Common Mis-Spelling: controlled variable Importance of the Control Variables Although control variables may not be measured (although they are often recorded), they can have a significant effect on the outcome of an experiment. Lack of awareness of control variables can lead to faulty results or what are called confounding variables. Noting control variables makes it easier to reproduce an experiment and to establish the relationship between the independent and dependent variables. For example, say you are trying to determine whether a particular fertilizer has an effect on plant growth. The independent variable is the presence or absence of the fertilizer, while the dependent variable is the height of the plant or rate of growth. If you dont control the amount of light (e.g., you perform part of the experiment in the summer and part during the winter), you may skew your results.

Explanation and Chart of Ser Versus Estar

Explanation and Chart of Ser Versus Estar There are few things more confusing for beginning Spanish students than learning the differences between ser and estar. After all, they both mean to be in English. Differences Between Ser and Estar One way to think of the differences between ser and estar  is to think of ser as the passive verb and estar as the active one. (The terms arent being used in a grammatical sense here.) Ser tells you what something is, the nature of its being, while estar refers more to what something does. You might use soy (the first-person present of ser, meaning I am) to explain who or what you are, but youd use estoy (the first-person present of estar) to tell what you are being or doing. For example, you might say, Estoy enfermo for I am sick. That would indicate that you are sick at the moment. But it doesnt tell anyone what you are. Now if you were to say, Soy enfermo, that would have a different meaning entirely. That would refer to who you are, to the nature of your being. We might translate that as I am a sick person or I am sickly. Note similar differences in these examples: Estoy cansado. (I am tired.) Soy cansado. (I am a tired person. My nature is to be tired)Estoy feliz. (Im happy now.) Soy feliz. (I am happy by nature. I am a happy person.)Est callada. (Shes being quiet.) Es callada. (Shes introverted. Shes naturally a quiet person.)No estoy lista. (Im not ready.) No soy lista. (Im not a quick thinker.) Another Approach to Ser vs. Estar Another way of thinking about the two verbs is to think of ser as being roughly equivalent to equals. Another approach is that estar often refers to a temporary condition, while ser frequently refers to a permanent condition. But there are exceptions. Among the major exceptions to the above way of thinking is that ser is used in expressions of time, such as Son las dos de la tarde for Its 2 p.m. Also, we use estar to indicate someone has died- quite a permanent condition: Est muerto, he is dead. Along that line, estar is used to indicate location. Estoy en casa. (I am at home.) But, soy de Mà ©xico. (I am from Mexico.) Ser, however, is used for the location of events: La boda es en Nuevo Hampshire. (The wedding is in New Hampshire.) There are also a few idiomatic expressions that simply need to be learned: La manzana es verde. (The apple is green.) La manzana est verde. (The apple is unripe.) Est muy bien la comida. (The meal tastes very good). Note that sometimes estar is often modified by an adverb such as bien rather than an adjective: Estoy bien. (Im fine.) Although rare, there are a few situations where you can use either ser or estar. A married man  describing his marital status could say either Soy casado or Estoy casado. He might be more likely to use soy because he considers being married as part of his identity, although he might use estoy to indicate that he had been married recently. Present Conjugation of Ser and Estar Both ser and estar are irregularly conjugated. Heres a chart of the indicative present tense: Pronombre Ser Estar Yo soy estoy Tà º eres ests Él, ella, usted es est Nosotros somos estamos Vosotros sois estis Ellos, ellas, ustedes son estn Sample Sentences Susana es atenta y con buena comunicacià ³n. (Susana is thoughtful with good communication skills. Ser is used with a personal quality.)Susana est atenta a la situacià ³n de su amiga. (Susana is attentive to her friends situation. Estar is being used to characterize behavior.)Roberto es nervioso como mi hermano. (Roberto is as nervous of a person as my brother is. Ser is used here for describing what kind of person someone is.)Roberto est tan nervioso como mi hermano. (Robert is as nervous as my brother is now. Estar is used for an emotional state that is independent of personal qualities.) Quick Takeaways Ser and estar are the two verbs most frequently used as the equivalent of the English to be.Ser typically is used in describing the nature of someone or something.Estar typically is used in referring to a state of being that isnt necessarily innate.