Some fifth grade science fair ideas include discovering what household chemicals ward off insects, which dyes people can mix with water to alter the color of flowers and whether people possess the same sensitivity to odors. Another possible fifth grade project involves experimenting on the effect of storage temperature on popcorn popping.
Fifth graders can choose one type of insect, such as flies or ants, and use herbs, spices or other ingredients to create a nontoxic solution that can repel insects. To determine if storage temperature affects popcorn popping, students should put popcorn in different locations, including the freezer, the lower compartment of the refrigerator, a warm area and a place with room temperature. They should pop the same amount of popcorn from each sample and count the number of unpopped kernels.
To find out if people have distinct sensitivity to smell, students should allow test subjects to smell a sample of vinegar, lemon oil or another scent. The test subjects should record what they smell and the time they recognized the smell. Students should compare the results and see if the test subjects smelled different scents at the same time. Fifth graders may also find it interesting to discover the rates at which food cooked in the microwave and on the stovetop cool by using a thermometer to measure heated foods.