Okay--revising the experiment for use of plants (poinsettia or ivy): I think that even the poinsettia would show changes during the three week period, but I would be worried about leaf drop/loss with the poinsettia. You probably should do the following during the experiment: 1) count the number of leaves on each plant. If you are within a leaf or two, remove a leaf or two from the leafier plant near the bottom (the worst-looking leaves) to make the number even. Do this before you start the experiment. 2) Weigh the plants. The analysis might not show any differences between the two regimens in terms of net growth, but when divided by weight might show a difference. Try to make sure that the plants start with approximately equal soil moisture levels--you could use a soil moisture meter to make sure that this stays the same. Weigh the plants every time you measure them, and if you can measure soil moisture, do that every time as well. An inexpensive proxy for a soil moisture measurement would be to place a square or circle of paper towel or coffee filter on to the surface of the soil, and measure how long it takes for the paper to become damp. 3) The place where you should see significant change is not perhaps in overall length of the plants, but the length of the stems between leaves (length between leaf nodes). To measure this difference effectively, put a small piece of twist-tie around the bases of the leaves you want to measure between so that you can find those leaves and stems again. Don't make the twist-tie very tight. You could use yarn and tie it loosely, as well. Don't make the tie or yarn pieces any bigger than absolutely necessary. If you wanted to be really systematic, you could get those little jewelry price tags that attach with a thread loop and number the tags. For your introduction and conclusions, you will want to look up information on the types of light (just like I mentioned with the seed experiment) and information on "etiolation". Etiolation, or lengthening of the stem between leaf nodes is what you would expect to see with a lack of light or with the "wrong" kind of light. The suggestions I made about using a light meter still hold, because another question that should be asked is whether it's the distance to the light source that may cause lengthening. By weighing the plants at each point, you can also control for additional biomass (plant growth) production. My guess is that the plants in both groups would be about the same--but that the stems and leaves under one treatment would be thinner and longer. If you really want to have fun with the biomass portion, at the end of the experiment, compare the differences in the plants visually (and note those differences), then dump the plants out of their pots, rinse the plants clean of as much soil as humanly possible, and leave the plants to dry. THEN weigh the plants and compare the masses. Which treatment, if any, produced the most biomass? Was there any difference in the size of the root mass? I realize that with the exception of weighing, these observations are more subjective and qualitative, but it could lead to more sensible data analysis and better subsequent experimental proposals. Don't forget to compare the color and quality of the leaves in both plants: one group of plants will probably have leaves that tend more toward yellow, and one more toward green. You could use something like a process color chart or embroidery floss sample card to describe the differences in color more accurately. I hope that you aren't absolutely overwhelmed by all this--I get into science and things just take off...

I would use a potted rose bush,with a rose variety with single petaled blooms. It depends on the time of year the fair will be held. What would be blooming then? The simpler the structure of the blooms,the easier it is to demonstrate pollenation. Cross pollenation would be merely taking pollen from one plant and putting it on the female flower parts of a different variety.Self pollenation is taking pollen from one flower on a plant and pollenating the same bloom or a different bloom of the same variety. The first thing he needs to do, is to learn the latin names of the male and female flower parts.There are many sources of information,with pictures,on the net. Try searching the net,using Pollenation,plant breeding,hybridization,crossing plants. Remember that google is limited and other search engines may give better results. Del

I am a teacher, and we did an experiment like this last year in my 4th grade science class. It went like this: We took two common Dieffenbachia plants, both potted in ordinary (no added fertilizers) potting soil. Over a period of weeks, we added some all-purpose fertilizer to just one of the plants. Both plants were getting the same regular water and sitting in the same windowsill. The fertilized plant seemed to put on a little more growth. Nothing outstanding. Then, after 6 weeks or something like that, we stopped watering both plants, and watched to see how long it took for signs of distress to appear. The results were striking. The plant without fertilizer quickly started to droop and turn brown with no water. The fertilized plant kept its color and form many times longer, only starting to show stress about the time that the other plant looked almost completely dead. It was interesting. Hope that gives you some ideas. Heck, take the whole experiment if you want. I hope your son does well. good luck!

If you google vermicomposting and kids you can get all kinds of ideas. The food idea sounds do-able in 3 weeks and taking pictures is a great idea. Some other food ideas: In one container put fresh chunks of food, in another food that's been frozen and thawed, in another food that has been liquified in a blender, in another cut up food that's about a week old . Which do they start eating sooner? There's a study on why worms seem to gather together. They thought maybe they left a trail (as ants do) and the other worms would follow. In the experiment, they had a central area with 2 choices of ways to go to food. They put one worm in the central area to see where it went. They then added other worms. They didn't necessarily go where the first one did (therefore, they concluded that they weren't leaving a trail). When they put a number of worms in together, they tended to all go to the same place. Their conclusion was that they just have a herd mentality and tend to follow other worms. Wouldn't hurt to try it out yourself. Some of the foods they don't like are citrus, onions, garlic. They love melon. Freeze a slice and thaw (so that you're killing the fruit flies--I didn't freeze mine the first time and I was really sorry).