When it comes to selecting a topic for a science fair, ensure it is something the child is interested in, be it plants, animals or the human body. Once the general area is determined, the student should then pick a question that she can answer using the scientific method that will be the basis for the project. The scientific method requires the child to formulate a question and create a hypothesis, which he then proves or disproves through a series of experiments or observations. All the experiments should not harm the animals, plants or people being experimented on.
Here are several questions from About.com involving amphibians, reptiles and fish that can serve as the biology science fair project idea: Does temperature affect tadpole growth? Does magnetism affect limb regeneration in newts? Does the size of a population of fish affect growth? Does the amount of light affect fish activity?
If the child is interested in birds, About.com has these questions to consider for developing a science fair project: What factors increase egg-laying in birds? Do different bird species prefer a particular color of bird seed? Do certain bird species prefer one type of habitat over another?
Insects have the widest species variety in the animal kingdom, making them a rich mine for biology science fair project ideas. Here are just a few questions to think about from About.com: How does temperature affect the growth of butterflies? How do insects adapt to pesticides? Does light or heat attract insects to lamps at night? What substances do mosquitoes find attractive or repellent?
About.com provides a series of questions about mammals suitable for science fair projects. Among them: Does light variation alter animal sleep habits? Does music affect an animal's mood? Does colored water affect animal drinking habits? Which animal sense has the greatest effect on short-term memory?
Possibly the easiest to pull off as there's no need to collect animals, human body experiments make good science fair projects. About.com has amassed a list of human body experiments that includes: Do colors evoke human emotions? Does a person's BMI affect blood pressure? Does exercise affect lung capacity? Do food smells affect saliva production? Is yawning contagious? Does exercise affect memory retention? Which sense (taste, smell, touch) is best for identifying foods?
Another simple source of biology science fair project ideas is the plant kingdom. Plants provide a host of experiment opportunities. About.com lists a few: Do different colors of light affect the direction of plant growth? Does water salinity affect plant growth? Do fertilizers extend plant life during drought? Does soil pH affect plant growth?