I would stick with a single food item in each bin, by weight, and try for items which have a similar water content.

However, this experiment doesn't really prove anything. There are lurking variables, like microorganisms in the bins assisting in food breakdown and the normal decomposition rate of the food items. Also which one the worms "prefer" is of dubious importance versus the chemical content of the final compost or castings.

Perhaps the experiment can be reworded to "which food items compost most quickly in a vermiculture bin." Set up 5 bins of equal parameters and worms. In each bin, feed the same 3 type & quantity of food in the same place (i.e. left, right middle).

Then, see which food is gone first. The student could also periodically count the worms in each bin section to see which food has attracted the most worms to help judge if the worms are key to which one is composting the quickest.

If most of the bins are the same you have a good conclusion. If the bins are not the same, you might be able hypothesize that herd behavior is more important than food preference.

"However, this experiment doesn't really prove anything. There are lurking variables, like microorganisms in the bins assisting in food breakdown and the normal decomposition rate of the food items."

I believe the "control" mentioned will help compare with the normal decomposition rate".

I am hoping that microrganisms are going to be similar in the bin and also something not controllable. We will freeze all food before hand (control and samples) to try eliminate any larger insects from joining in the party.

I was thinking of having an assortment of food, including something like a orange peel. Something that people say worms may not like as much.

This is a 5th grade science fair project and not a study at UCLA. I am sure there will be a few flaws that can't be overcome with the procedure. The trick is to make sure he knows of them when someone asks him about it.

I like the "Which food items compost most quickly in a vermiculture bin." as a title except it sounds close to a comparison study which we will try to stay away from. It's hard to find a mixture of a tittle that doesn't sound like "which is best' and a title that is asking to much.

We are also not interested in final chemical content or castings. That would probably be way past what is needed for a science fair project.

What worms prefer also sounds like a comparison study to me. Here's another variant:

What is the rate of increase that vermiculture contributes to decomposition of ?

Start with the same bedding material (by weight and type), feed the same food and control other inputs/environment. Without existing vermicompost or castings in the bedding, it should help control any other microorganisms except any actively living on the worms, which seems to be a reasonable factor to include as part of normal worm activity.

Measure food in grams as input; periodically weigh recognizable uncomposted food scraps and bedding to determine rate of decomposition, which will make a nice graph. Weigh compost at the end. (Actually, an inedible bedding would be better but I can't think of any that would be acceptable to the worms.)

If you want to increase the experiment complexity, have the experimental bins contain different numbers of adult worms to see how that affects the rate of decomposition.

I would also select one food or one food type (like "vegetable scraps") that can be expected to full decompose in the available time frame and that worms do not actively avoid.

I would feed them all identically. I would freeze scraps, thaw, then blend (not what I normally do) adding identical amounts to each bin. Eight small 10 gallon bins might be good. The bedding would be the easyest component to change. The same weight of identically shredded, newspaper, office paper, cereal cardbaord, corrigated cardboard, TP roll cardboard. The constant could be a mix of them all. The end result would be how well a plant grown in the castings grow. But then that would be my experiment and only an honorable mention. I bet a 5th grader could play with worms for a few weeks, you have the time, and come up with a first, second or third place experiment. I suspect that not all adult worms are identical. How does one determine a worm just starting to lay eggs and a worm at the end of life?

Unless you are already committed to that experiment, you might want to browse through redwormcomposting.com Bentley has documented many interesting experiments.

Here is a link that might be useful: RWC

I'm assuming this experiment is being done indoors--otherwise, that open-air control is asking for trouble. Worm food preference is easier to demonstrate in the short-term than you might think (stick some cantaloupe in a bin some day, and watch them come wriggling! Like kids to an ice cream truck). Dislikes aren't always immediately obvious. They're not vampires, to squeal and cringe away from the garlic...or at least, mine aren't. But some foods worms "don't like" still decompose fairly quickly in a bin, while other things they seem to appreciate are fairly durable. Eggshells left in halves, for instance.

Not sure a single word of that was helpful, sorry. Good luck!

DSF

Thanks for all t he suggestions and yes it will be done indoors.
Ill also check out redwormcomposting.com for what they say there.

could you feed them the same foods but change the bedding in each?

Maybe 1 with no bedding at all, one with newspaper one with coir?

I would love to know if coir is useful and worth buying for worms? I did not buy any but my worms came with some.

Karen

"One last thing is for the student to know why their experiment is important in the real world."

One of my problems with the original hypothesis of which kitchen scraps would a worm prefer is how that makes a difference. It's not practical to separate food scraps into separate components. You might show that worms prefer watermelon rinds to beans but have you ever heard anyone complain about the amount of watermelon rinds causing problems at the landfill even after the 4th of July picnic?

In this world of 'going green', I think I'd look at items that do present problems at the landfill but should not.

A recycling company wants the easy to recycle stuff like newspaper, magazines, junkmail and old telephone books. Even in our city where we now have an active recycling initiative for paper and plastic we have things that are routinely sent to the landfill.

A couple things come to mind. One is the papertowels from a restaurant or airport restroom. You could probably even get the information from the airport to compute the tonnage of waste paper they deal with.

Another is disposable diapers -even though human waste is probably not something I would think a young child should be exposed to. And I'm not sure how well the worms can handle decomposing diapers anyway.

A better choice would be lawn scraps. Particularly now that this is the time of year people will sending tons to the landfill instead of composting it themselves. You could even separate the lawn refuse into pure grass clippings vs chipped shrubbery scraps.

I am aware that these will heat up and all that but you can do a week of precomposting them all after innoculating them with a measured amount of casting tea before adding the worms.

The experiment would then not be a preference study but rather one of efficiency. Perhaps a mixture as another variable. After a specified time, sift the vermicompost for castings and compare with unprocessed material. You can do both bulk and weight comparisons.

Another possible experiment- or possibly a side experiment that would have a real practical application- might be the importance of 'education' or backup to new vermicomposter. If you could prepare three identical bins: Give one bin to a relative/ friend, with a printout with instructions and let them at it. Ask them to log the amount of food composted, list any problems they ancounter and finally evaluate their attitude to the experience at the end of a given period. Give another bin with the same information but provide backup by phone or e-mail if they encounter problems. And finally keep one bin yourselves and log the same variables.

Two questions:
Do you currently compost with worms?
Would you consider a worm environment experiment that has nothing to do with worm food?

cathd66's June 5 idea has megga winning possibilities. If I was a judge it would catch my eye. I think because it involves more people, it makes it a more lively and exciting project. It spreads vermicomposting knowledge. It gets the student talking with many people and out into the world. Include more bins for students who show interest. Imagine, the coolest kids on the block will be the ones with vermicomposting bins to test. Geek heaven. 10 gallon rubbermaid would be good. Same instructions. Phone help yes. Or they can look on line to save the life of their bins. I would do 10 people. Maybe even let the people get their own bins. Title 10 people, 10 bins, 10,000 worms, 1 winner. Determined somehow. steamyb's criptic post has me interested. I bet it is a great idea. I'll take the bait. Is there a worm crawling up your sleeve steamyb?

I have an idea for an experiment /science project that would serve not just the vermi-community (feeding or food issues), but would indirectly benefit more people by making vermicomposting easier for folks just starting out. Besides the fact that feeding and food issues are limited to measuring garbage (yuck) and the bedding ultimately becomes worm food as well. Weighing castings (double yuck) will surely stop most people from ever wanting to start with worms.
So xpoc454:
Do you currently compost with worms?
Would you consider a worm environment experiment that has nothing to do with worm food?

Here is a clue:
http://forums.gardenweb.com/forums/load/verm/msg050138164413.html?14

DonÂt worry if you decide to pass on this. I have all the stuff in place to do this experiment; I am just short of time right now.