Science Buddies: "Ask an Expert"

Hi All.

I am currently working on an experiment investigating how water content in an unripe apple will affect it's sugar content as it ripens.

I've been googling for days, been to the library countless times, and I the only things I find are random obscure answers that either make no sense or have nothing to do with what I'm looking for . So here I am with some problems I'm stumped with:

1. Are fruit peels semi-permeable? (I'm trying to place unripe apples in different molar solutions of sugar to change the water content of the fruit)

2. Is ethylene able to permeate through or penetrate a ziploc-bag?

3. Do all bananas produce/emit the EXACT (or ALMOST EXACT) same amount ethylene? (Assuming they are all the same type, from the same family, same genus, etc...)

4. What is the minimum amount of ethylene that is able to stimulate an apple to start ripening, and will remain a large influence on the apple's ripening process?

5. What is the binomial nomenclature for the apple: "Cox's Orange Pippins"? Do i just write Malus Domestica "Cox's Orange Pippins"?

6. If i were to saran wrap my peeled apples to prevent oxidation (assuming that I need to take off the peel to allow osmosis in the sugar solution), will the apples still be able to ripen?

7. If the apples are not able to ripen in saran wrap, is there any other way to prevent my apple samples from rotting for 4 weeks, and will still allow ethylene to reach them?

8. I'm also trying to dilute iodine tincture, and many sources say that I should dilute the soultion 10 parts water and 1 part iodine solution. Does that mean that, assuming I have 25ml of iodine tincture, I have to mix the tincutre with 250ml of water?

...and that's about it. If you are able to answer ANY of the questions that I posted, then I would greatly appreciate your help!

Hi-
I'm not sure about some of your questions, but here are a few answers to get you started:
1. Are fruit peels semi-permeable? (I'm trying to place unripe apples in different molar solutions of sugar to change the water content of the fruit)
- I think apple peels have a very low level of permeability. Here's a quick test you can do: mix some sugar water in with food coloring and leave an apple in there - after a few days cut it open and see if any food coloring has made it through?

2. Is ethylene able to permeate through or penetrate a ziploc-bag?
- ethylene gas should not penetrate plastics

3. Do all bananas produce/emit the EXACT (or ALMOST EXACT) same amount ethylene? (Assuming they are all the same type, from the same family, same genus, etc...)
-I would say no. Biologically, that wouldn't make much sense. Instead of assuming all bananas are emitting the same amount of gas, why don't you mix a few bananas that are approximately the same size for each experiment. That way you'll wind up with an average.

5. What is the binomial nomenclature for the apple: "Cox's Orange Pippins"? Do i just write Malus Domestica "Cox's Orange Pippins"?
Malus Domestica is the general species that apples in general fall under, Cox's Orange Pippins is the variety.

8. I'm also trying to dilute iodine tincture, and many sources say that I should dilute the soultion 10 parts water and 1 part iodine solution. Does that mean that, assuming I have 25ml of iodine tincture, I have to mix the tincutre with 250ml of water?
Yes - that's just a standard 1:10 dilution (for every 1ml of iodine, you need to add 9ml of water) - so 25ml of iodine in 225ml of water (for 250ml total)

Hope that gets you started.

Stephanie