Something that is changed during an experiment For example, if you were testing the effect of mass on pendulum motion, the independent variable is mass because you are changing the mass placed on the pendulum.
The variable in a system that does not depend on the other. Typically, it tends to be the one that changes the other.
For example, if you have a chart that shows how many calories you burn after exercising, which one does not depend on the other? Exercising does not depend on how many calories you burn. Which one changes the other? Exercising changes the other.
For example Weight = mass * 10. If mass is indep. variable then it just means you decide what number do you want it to be. Let's say 20 as you wish. Then according to it Weight = 200. If Mass is 10 then Weight is 100. As you see when you change mass weight also changes. Weight depends on mass. But mass can be whatever. Of course, mass also depends on weight. But in this case as we chose mass as an independent one to see what's going on with weight. Here mass is indep. and weight is dependent (on mass).