What is a dependant and independent variable?
An independent variable can assume values arbitrarily within any specified constraints. A dependent variable does not have this freedom. Its value is governed by the function relating it to the independent variable. Example: Consider a closed vessel containing only water and its vapour. The temperature of the vessel can be varied to any arbitrary value below the melting point of the vessel. It is an independent variable. The vapour pressure of water above the water surface cannot be varied at a fixed temperature. This variable (called the saturated vapour pressure) DEPENDS on the water temperature.
