Fifth grade students often enjoy experiments that involve growing and caring for plants. One example of an experiment in the plant sciences is planting bulbs at varying depths to explore the effects of depth on the health of the plant. Alternately, students can discover the hidden fall colors of green leaves by grinding up leaves from deciduous trees and using rubbing alcohol and a coffee filter. As the alcohol breaks down the leaves, the filter will absorb the chlorophyll and other compounds that contain the fall colors of the leaf.
If you can care for small animals in your classroom or home, fifth-grade students may enjoy learning about them through some non-harmful experiments. For example, students can incubate and hatch eggs for a local farmer to explore how birds incubate eggs. Alternately, set up an aquarium and allow students to monitor the aquarium's pH levels. Students can then determine the optimum pH for goldfish or to explore the effects of pollution from waste on the pH levels of the tank. Students may also enjoy examining different sets of animal tracks and playing "detective" to discover the animal that made the tracks.
Experiments in physics often seem magical to fifth graders because physics is a new topic for them. The underwater candle experiment is a simple and exciting project. Tape a taper candle to the bottom of a deep bowl with duct tape. Fill the bowl with water until the water level reaches just below the wick.The candle will burn down completely, leaving a hollow wax shell. Alternately, make catapults out of popsicle sticks and varying sizes of rubber bands and have the students measure how far the different catapults can shoot marshmallows.
Fifth grade is the ideal time to introduce some of the more complex ideas in the earth sciences. One often-used project involves making a volcano out of papier-mache and making it erupt with a baking soda solution. Another idea is to grow crystals on charcoal briquettes using laundry detergent, bluing and a few other household ingredients. Fifth graders also enjoy classifying rocks and crystals and comparing their properties. Ask them to choose a category of rock or crystal and make a poster that displays pictures and samples of the rocks.