There are different types of variables in science but broadly speaking, variables are mainly quantities that may change. As the name suggests, it can be and is usually changed or controlled by changing certain conditions and factors which may affect it and cause the change to take place.
There are three main types of variables and each has their own use and purpose.
The first of the three types of variable is independent variables whereby the variable can be changed by manipulating certain factors in an experiment in order to get different results each time because of the change. By way of example, solubility is affected by temperature changes. So if you try to dissolve sugar in cold water, this would take you more time but if you heat up the water, you’ll see that the sugar gets dissolved faster.
The next is the dependent variable which depends upon the independent variable itself.
How the independent variable is manipulated and affected is what would have an effect on this variable. Where the solubility of sugar in water is concerned, the dependent variable is the solubility since it is dependent upon the change of temperature of the water.
Then, you’ve got the third of the three types of variables- the controlled variable. This variable is a constant one and will not be affected by manipulation of factors that affect dependent or independent variables.
Pharmacies and various scientific organizations use various types of variables to see the effect they would have on certain things, processes and people by manipulating various factors. For example, whether or not changing the ammonium content in the soil would have an effect upon plant growth or the types of plants that grow on that soil is the kind of experiment that scientists, involved in agriculture, would carry out to determine how to improve the quantity and quality of the crops that grow on that soil.
Pharmacies use different types of variables to see how increasing, decreasing or manipulating certain factors would have an impact upon our bodies. Recently, for example, many scientists are involved in the research of how increasing or decreasing vitamin D contents in an average human being would affect their health overall. The findings would then be used in order to help these scientists understand how vitamin D affects us if we eat more foods (or less foods) that consist of vitamin D.
Variables are also used when making nuclear weapons.
How much such weapons would affect people who are targeted and in what ways is something that is constantly being looked into and this, too, is affected by variables. Variables are also used when making food products- how increasing or decreasing certain variables would affect our bodies is also something that is determined by carrying out experiments with different types of variables.
Cosmetic companies also use variables to see how the manipulation of various types of variables would affect, say, our hair, bodies and skins due to the use of shampoos and soaps.