Science Buddies: "Ask an Expert"

My science project is to find a relationship between a fruit or vegetable's density and its nutritional value (based on nutriets of my choosing ex: Vitamin A, Vitamin C, Potassium, Iron, Calcium, etc. in mg.) By finding a strong correlation of the two in a scatter plot. The Density will be the Independant Variable while the Nutritional Value will be the Dependant Variable. But i am confused. Would i measure each one in mg, and put the amount of each nutrient for each fruit/vegetable all on the same graph (and have a different color dot to resemble a different nutrient)? Or would I make a seperate graphs for each different nutrient? In case I didn't very well explain this, here's the website where I got my project idea from -----> http://www.education.com/science-fair/a ... nutrition/
Thank you.

Hi there,

I have a couple of questions about your project that will give me a better idea of what you're trying to test so that I can give you more helpful advice.

What is your main question? From your description, you are wondering whether there is a relationship between a fruit or vegetable's density with its nutritional value. What is your hypothesis then? Do you think that the denser the fruit is, the more nutrition is present in the fruit? I took a look at the link you sent me, and I don't quite understand the logic behind that study. There is no reason to believe (that I can think of) that a food that is denser will have more or less nutrients than something that is less dense. Plus, as that webpage mentioned, different foods will have different nutrients, so I don't know how you can compare whether one food is more "nutritious" than the other when they have different contents. What is your definition of "nutritious"? If a food has more of the nutrients that you choose, you will categorize that as more healthy than other foods that don't have nearly as much?

Perhaps I'm just not understanding this correctly. Other experts, please chime in if you have a better idea of what is going on, and correct anything I've interpreted incorrectly.

Feel free to post back with more questions and we'll try to help you work this out.

Connie

Thank you, that was a fast response. I think "nutritional value" means the amount of an individual nutrient (mg) for a fruit. So I think I'm supposed to make a different chart for every nutrient. I know how some fruits have nutrients that others don't, but what if I chose nutrients that the fruits I chose all had? Also my hypothesis was "If the density of fruits has a relationship with its nutritional value, then the denser the fruit, the more nutritious it is because there will be a greater concentration of nutrients in that fruit per ml. Or what do you think? Also if my hypothesis is wrong, and there isn't a strong correlation between density and nutritional value, I guess that will go in my conclusion right? Because that's the question I'm trying to answer.

That sounds reasonable to me. It'll probably make it a lot easier to compare if you chose fruits and/or vegetables that you know have the same nutrients like you had mentioned. That's a good hypothesis, and yes, if you happen to not find a correlation between density and nutritional value, then that can definitely go in your conclusion.

Thank you so much for your help! This really did help a lot!