What is control and variable of a scientific lab?

-----%26gt; please n() mean answers =(What is control and variable of a scientific lab?
';A control'; is a standard, and ';a variable'; is the thing you change.





Let's say you are going to do an experiment on how fast a piece of bread will mold, depending on a temperature.





Before you can say a bread at temperature F will mold X times faster, you need to know how fast the same bread will mold at the normal temperature.





SO.....


You define 75F as the normal temperature (for example) and let a piece of bread mold in this environment. Then measure the length of time it takes to develop mold. That is your control.





Then you raise or lower the temperature (VARIABLE) and measure how long it takes the bread to mold. Now, you can compare these measurement to the control and say they mold X times faster or slower at higher or lower temperature.





Establishment of a good CONTROL is one of the most important thing in conducting a valid experiment. Another is to limit the VARIABLE to just one. If your experiment is about the tempearature as a variable, you must take care to keep everything else constant. For example, humidity and lighting conditions. If they change, you have more than one variable, and your result will be invalid.What is control and variable of a scientific lab?
control is the substance you leave in it's original state -- the variable is the substance that you're working with (then you compare the two for effect.