# What is the difference between a parameter and a variable?

1. Jul 30, 2010

### arroy_0205

It seems (to me) that parameters are also kind of variables in descriptions of physics. I am confused what makes a paramater different from a variable. Can anybody please explain this?

2. Jul 30, 2010

### fatra2

Hi there,

From my point of view, here are a few parameters: g=9.8m/s2, c= 300'000km/s.

Variables are the values that you are trying to find in any model. The model bases itself on different fixed values, or parameters.

Cheers

3. Jul 30, 2010

### owlpride

From a mathematical point of view, a parameter is a variable that is meant to stay fixed in a certain application. For example, in middle or high school you studied the three-parameter family of functions

f(x) = ax^2 + bx + c.

While the three numbers a, b, c are variables, you want to think of them as fixed and let only x vary. To distinguish the roles of a,b,c on the one side and x on the other, we refer to a,b,c as parameters.