5 (b.a.) The Three Types of Variables
I am doing an experiment. I have two plants. Both the plants are in pretty much the same location and get the SAME amount of sunlight. This first plant however I water every single day. This plant however I only water every OTHER day. So Jacob in this experiment what do you think it is that I am testing?
Well since they’re the same type of plant and in the same location are you testing how well they grow depending on how much water they get?
That’s absolutely correct Jacob, I am MEASURING how much the plants grow based on how much water they get.
So why did you place them both in the same place wouldn’t been fun to put one somewhere and one somewhere else, and maybe maybe have different amounts of soil. Oh we can also change ah what music we play for them.
That actually wouldn’t work in this experiment. Do you see the PROBLEM?
We’re changing too many things. At the end of my experiment I couldn’t say that it was the water or the sunlight that made it grow more. Cause I changed too much.
In order for an experiment to be fair you can only change one thing at a time. Everything else in the experiment should stay the same. In your experiment the thing that you change is called the independent variable.
Independent variable! So Mr. Konan is there a name for everything else?
What do you mean Jacob?
You know, like all of the stuff that we could have changed but we didn’t. Like keeping the plant in the same location, or letting them have the same amount of light or using the same kind of plant.
Yes, they do actually have a name. They are called the controlled variables.
Controlled variables! But wait wasn’t there one last thing you wanted to tell me about?
Yep that is right Jacob, and the other things is called the dependent variable.
Wait I know what dependent means. It means to depend on something like how I depend on my parents to give me a place to live. In our experiment the dependent variable must be something that depends on something else. Like in our case how tall the plant got depended on how much water you gave it. Alright I get it, when I do an experiment the thing that I’m measuring is my dependent variable, the thing that I change and test is my independent variable everything else should stay the same those are my controlled variables.
So for your next experiment all you have to remember is that you need one independent variable and remember that is the thing that you change, one dependent variable and again that is the thing that you are trying to measure. And if you keep everything else the same you should have a fair test.
Well since they’re the same type of plant and in the same location are you testing how well they grow depending on how much water they get?
That’s absolutely correct Jacob, I am MEASURING how much the plants grow based on how much water they get.
So why did you place them both in the same place wouldn’t been fun to put one somewhere and one somewhere else, and maybe maybe have different amounts of soil. Oh we can also change ah what music we play for them.
That actually wouldn’t work in this experiment. Do you see the PROBLEM?
We’re changing too many things. At the end of my experiment I couldn’t say that it was the water or the sunlight that made it grow more. Cause I changed too much.
In order for an experiment to be fair you can only change one thing at a time. Everything else in the experiment should stay the same. In your experiment the thing that you change is called the independent variable.
Independent variable! So Mr. Konan is there a name for everything else?
What do you mean Jacob?
You know, like all of the stuff that we could have changed but we didn’t. Like keeping the plant in the same location, or letting them have the same amount of light or using the same kind of plant.
Yes, they do actually have a name. They are called the controlled variables.
Controlled variables! But wait wasn’t there one last thing you wanted to tell me about?
Yep that is right Jacob, and the other things is called the dependent variable.
Wait I know what dependent means. It means to depend on something like how I depend on my parents to give me a place to live. In our experiment the dependent variable must be something that depends on something else. Like in our case how tall the plant got depended on how much water you gave it. Alright I get it, when I do an experiment the thing that I’m measuring is my dependent variable, the thing that I change and test is my independent variable everything else should stay the same those are my controlled variables.
So for your next experiment all you have to remember is that you need one independent variable and remember that is the thing that you change, one dependent variable and again that is the thing that you are trying to measure. And if you keep everything else the same you should have a fair test.