Science Buddies: "Ask an Expert"

Hello,
my project is on the whether the density of a fruit affects how much nutrition (potassium, fibre, vitamin C) it has. I test this with apples and I was wondering if there is any way to make the purpose more complex as the experiment seems too easy for my grade level (9).
Thanks

What other fruits are you testing and what nutrients are you comparing? What is your hypothesis?

There is a lot of natural difference in the nutrient content of fruits and vegetables that has nothing to do with how much they weigh per milliliter. You've heard the old saying about comparing apples and oranges--well, if you picked vitamin C as the nutrient to compare, an orange would win regardless of its density.

How are you determining density of the fruit? Would you compare an equal weight of the fruit or an equal volume? For a denser fruit, an equal volume would weigh more than an equal volume of a less dense fruit. Fruits also vary a lot in their water content. If you compared equal weights of apple and watermelon, the apple has a lot less water than the watermelon so might have more of some nutrient.

I would suggest selecting maybe 4 or 5 fruits and comparing equal weights for the number of calories they contain and then comparing them for fiber, which is important for health, potassium which is a necessary mineral for the nerves and blood system, and vitamin C and vitamin A which are necessary for protecting the body from free radicals and for a healthy immune system. If you still want to consider density, then you could compare equal volumes of the fruits and see what difference that makes in the relative amounts of specific nutrients.

Post again if you have more questions.

Sybee