Science Buddies: "Ask an Expert"

this is 4 davidkallman only and other people if they want to help to my question is: is the more amout of air going to make my apples turn brown quicker and is the least amount of air going to make my apple turn brown at a slower rate?

Hi pete!

I honestly don't know. Is it something you can test?

yes and why do u always say cheers at the end?

hi again!

I believe that having more air would increase oxidation because more air pressure puts more of the air into the volume of the apple, which will cause more collisions and a higher level of collision frequency inside of the apple. This leads to a higher oxidation reaction rate.

Hi Pete!

Thanks for the reply. Yes, testing is the way to go. "Cheers!" is my stand sign-off and represents an optimisism towards life.

Oops, optimism!

Hi Pete,

This is an interesting question! If the amount of air (do you mean just oxygen or the other elements, too?) surrounding an apple is what causes it to brown, then I have a question for you to think about: Theoretically, if you were able to place an apple in a true vacuum (with no air and, specifically, no oxygen), would the browning totally cease to occur?

Taking the other extreme, if you were able to increase the air pressure (amount of oxygen) above atmospheric pressure, would the rate of browning be increased? Based on what you have told us so far, it looks as though it would. However, at some point, the rate of browning will no longer increase - it cannot continue increasing forever. What do you think would cause the rate to eventually stop changing? (Hint: this is to do with the amount of molecules present and the surface area involved - Jessica gave you some ideas to consider in her posting.)

Anyway, I think you have a very interesting project - and please be sure to keep asking us questions if you are not sure of anything.

Good luck!
Geoff.