Yes, you are right! The ripe banana is producing ethylene and should speed up the ripening (conversion of starch to sugar) of both the pears and the apples, which are sensitive to ethylene. Unripe apples and pears would not contain much ethylene, so should ripen slower compared to fruit exposed to ripe bananas. Ripe pears and apples also produce ethylene, and if the starch in the fruit is already converted to sugar, you would not see any difference in the starch content
Here is a website that includes a good description of ethylene and its role in ripening fruit. The information in the first two paragraphs is good background information for your science project. Why is ethylene called the aging hormone of plants?http://postharvest.tfrec.wsu.edu/pages/PC2000F
The Wikipedia article includes the structure of ethylene and this information could be a helpful addition to your science board. http://en.wikipedia.org/wiki/Ethylene
Here is a link to the original article documenting the effect of ethylene on fruit ripening. This scientific article was published in 1962 and the authors used gas chromatography to measure levels of ethylene. There is data on the ethylene content of ripe bananas, apples, and pears, and please note that all of these fruits contained ethylene. I recommend including this article in your bibliography or literature cited section.http://www.ncbi.nlm.nih.gov/pmc/article ... 5-0067.pdf
Here is the information from this website on your display board.http://www.sciencebuddies.org/science-f ... oard.shtml
Since you project is due soon, you may not have time to repeat the experiment. If you do have time, then definitely set it up again using the firmest pears you can find. If you don’t have time to repeat the experiment, then you will have to present the results as is, and you will need to include a good explanation of your results. Since you results did not turn out as expected, be sure to include information on what you would do differently next time if you were to repeat the experiment.
Now, for the title of the experiment. Do you think that an overripe, spoiling apple would be producing a small amount of ethylene, or perhaps a very large quantity of ethylene? What would this do to the rest of the apples in the container, especially in a closed container? Please let me know what you think.
If your assignment is due soon, go back through your teacher’s assignment and make sure you have included all of the details that are supposed to be included. This is important in order to get the highest grade possible.
Post again if there are any last minute questions.