Variable question for my science project

[Caitlin]

I am doing a project on "How much water is in an orange?" I'm not sure what the variable is? Can you help? Caitlin

[donnahardy2]

Hi Caitlin,

This is a good question. I’m not sure what you did for your experiment, but you should have two variables. The first would be the different oranges that you measured. Did you measure the water content of more than one orange? If you did, then this would be your independent variable. Your dependent variable would be the percentage water that you measured in each orange.

The science buddies website has a good explanation of this important concept:

http://www.sciencebuddies.com/science-f ... bles.shtml

If you are wondering how to present your results, I think a bar graph would work well with this type of data. Put a bar on the x axis for each orange you measured; put the percent water on the y axis.

Let us know if you have any other questions.


Donna Hardy

[laurensfp]

Hi my name is Lauren and I am doing the same science fair project. I do see the dependent variable as being the weight of the water in the orange but I am still unclear as to the independent variable. I am taking 3 oranges and evaporating the water out and measuring the remaining solid part of the orange. This gives me the weight of the water. We are keeping the temp. and the air flow constent with a dehydrator and measuring the weight over time. My question I came up with is ,"how does evaporation affect the percentage of the water in an orange?" The dependent variable is clear but I am still unsure of the independent variable. I thought it was the time the evaporation took to remove the water from the orange and not the orange it self. I used the example of time as an independent variable to come up with my question and figured my variables.
DV - Liquid in the orange, by weight
IV - Evaporation, by time hours
CV - Solid of the orange, by weight
Food dehydrator (controlling the temp and airflow)

Thanks,
Lauren

[donnahardy2]

Hi Lauren,

You have a good question. The independent variable in your project is the individual oranges. You are measuring the moisture content of 3 different oranges, and the dependent variable will be the result of each orange. If you were using different types of fruit, the independent variable would be the type of fruit.

I hope this helps. Let us know if you have any more questions.

Donna Hardy

[deleted-71536]

Hi Caitlyn and Lauren,

Donna has given you some great advice. I like to remember it this way: the independent variable is the thing you change, and the dependent variable is the one that changes in response to the other one.

I hope that helps!

Heather

[deleted-71821]

Hi Lauren,
It sounds like you have a good understanding of the experimental process. I sometimes use the term "manipulated variable" instead of independent. It tells me that this is the one thing that I change or manipulate. The dependent variable will always be something you measure and, of course, the controlled variables are everything you can keep the same so that, when you are through, you can state your results clearly. My question to you is "Are you comparing the amount of water in different types of oranges?" or just in oranges in general? If it is just in oranges in general then you will try to select (by weight) three of the same type of orange (this is the number of trials) and we know we always do more than one trial. You mentioned air flow and temperature which are very important variables to control. You also will have time as a variable and the scale on which you weigh each orange at the end of the experiment. Can you think of any other things you should keep the same? Even though the weights may vary both before and after, the percentage of water weight should remain pretty much the same.
Hope this helps.
Carrol

[deleted-71821]

Hi Lauren,
I had one more thought on your project and that is whether or not this is an experiment or a demonstration. It might be a stronger design if you are comparing three different types of oranges for the amount of juice in them (important for orange growers). That wasn't quite clear to me.
Carrol