MartiNguyen
Posts: 1
Joined: Thu Jan 17, 2013 2:34 pm

### Dependent and independent variable

i'm doing a science fair project on the science of crispy potatoes and i don't know what is the independent variable or the dependent. Please help.

theborg
Moderator
Posts: 351
Joined: Mon Oct 03, 2011 12:26 pm
Occupation: US Air Force Space & Missile Operations

### Re: Dependent and independent variable

MartiNguyen,

Welcome to Science Buddies and thanks for the question. Your variables will be determined on what it is you are trying to test. Without understanding in more detail what your project entails, it is difficult to provide advice. If you could give some detail to your project question, hypothisis, etc... someone should be able to help with your question. In the mean-time, this site has a really good project guide, located here:

http://www.sciencebuddies.org/science-f ... ndex.shtml

It includes a couple of sections on variables and how to determine what they are.
Hope this helps.

theborg
----------
Science Buddies science fair guide:
http://www.sciencebuddies.org/science-fair-projects/project_guide_index.shtml

Science Buddies project ideas:
http://www.sciencebuddies.org/science-fair-projects/project_ideas.shtml

debra123
Posts: 4
Joined: Tue Dec 30, 2014 11:21 pm
Occupation: Special Education Teacher.

### Re: Dependent and independent variable

First to know What's a variable is

A variable is an object, event, idea, feeling, time period, or any other type of category you are trying to measure. There are two types of variables-independent and dependent.

Now come to that what's an independent variable?

An independent variable is exactly what it sounds like. It is a variable that stands alone and isn't changed by the other variables you are trying to measure. For example, someone's age might be an independent variable. Other factors (such as what they eat, how much they go to school, how much television they watch) aren't going to change a person's age. In fact, when you are looking for some kind of relationship between variables you are trying to see if the independent variable causes some kind of change in the other variables, or dependent variables.

now what's a dependent variable?

Just like an independent variable, a dependent variable is exactly what it sounds like. It is something that depends on other factors. For example, a test score could be a dependent variable because it could change depending on several factors such as how much you studied, how much sleep you got the night before you took the test, or even how hungry you were when you took it. Usually when you are looking for a relationship between two things you are trying to find out what makes the dependent variable change the way it does.

Many people have trouble remembering which is the independent variable and which is the dependent variable. An easy way to remember is to insert the names of the two variables you are using in this sentence in they way that makes the most sense. Then you can figure out which is the independent variable and which is the dependent variable:

(Independent variable) causes a change in (Dependent Variable) and it isn't possible that (Dependent Variable) could cause a change in (Independent Variable).

For example:

(Time Spent Studying) causes a change in (Test Score) and it isn't possible that (Test Score) could cause a change in (Time Spent Studying).

We see that "Time Spent Studying" must be the independent variable and "Test Score" must be the dependent variable because the sentence doesn't make sense the other way around.

tdaly
Former Expert
Posts: 1415
Joined: Sat Nov 08, 2003 11:27 pm
Occupation: Planetary Scientist

### Re: Dependent and independent variable

Hi MartiNguyen,

The other Experts have given you some helpful advice. I wanted to add a thoughts of my own to complement their replies.

For a science fair project, an independent variable is the thing you change in your experiment. The dependent variable is what changes in response to variations in the independent variable. Sometimes the dependent variable is called the response variable because is responds to changes in the independent variable.

For example, let's say you were doing an experiment to determine how oil temperature affected how people rated the crispiness of potato chips on a scale of 1 to 10. Your independent variable (the thing YOU change) would be oil temperature. The dependent variable would be how people rated the crispiness of potato chips fried at different temperatures.
All the best,
Terik