Plants are easy to work with for evolution experiments because you get results quickly. Students should explore crossing different types of plants. Kids should choose a plant such as a pea plant, like the kind Gregory Mendel used for his own genetic experiments. Plant two different types of pea plants, one with green seed pods and one with yellow seed pods. Cross-pollinate the flowers by dusting each flower with pollen from the other plant's pollen. Be sure you purchase plants or seeds that are not self-pollinating. Observe the results of the seed pods after cross-pollination, and track what happens in each generation of seed pods after cross-pollination in every generation.
Create a family for a kids' evolution experiment. Younger children should work on this simple project. Kids will cut out ovals from skin-toned colored paper. Using dark construction paper, children will cut out dark hair and eyes. Then, children will cut out light hair and eyes. Using a coin, the kids will flip it to get results of what a mother will look like. Heads might be that she has light hair, and tails will be that she has dark hair. Do this for the father. Place the right hair and eye color on each oval for the parent. Then flip the coin for the sex of the baby. Flip the coin for hair and eye color. Continue the experiment for the next generation.
The effects of pollution on evolution is another experiment for kids. Use daphnia, or water fleas, for an experiment. Set up a tank for the daphnia, where they will normally reproduce asexually, which uses one parent and one set of genes rather than two. This will be the control tank. Set up another tank where pollutants such as aluminum sulfate and lead monoxide will be added. Test the concentrations that will lead the daphnia to reproduce sexually, with two parents and two sets of genes, rather than asexually.
Kids can use online experiments to learn about evolution. One site called Pea Experiment uses Mendel's well-known genetics experiment as a basis of an online game. Kids will click a button to choose which peas are the parents and what their children should become. Then the plants will breed. Another website from PBS' "The Lost Tribes of Israel" offers children an experiment about genetics through the study of the Y-chromosome. It teaches children about DNA and mutation.