Conducting an experiment on how ethylene gas ripens fruit requires very few materials. In addition to a brown paper bag and a plastic bag, such as one from a grocery store, you will need fresh, unripe fruit, and materials for recording notes on how the experiment is progressing.The Science Buddies website suggests using green bananas; the ripening process of bananas is easy to recognize as the fruit turns from green to yellow to brown.
If your child or student is of an age at which she is able to understand the scientific process, have her hypothesize about what will happen in the experiment. Have the child predict whether the fruit in the paper bag or the fruit in the plastic bag will ripen the fastest. Have her take into consideration the fact that ripening fruits produce ethylene gas, which becomes trapped in the fruit's packaging. While this gas helps fruits to ripen naturally, a build-up of ethylene gas can lead to overripe and spoiled fruit.
After the hypothesis has been made, place one piece of the same fruit, such as green bananas, into the plastic and paper bags. Place the bags in the same location. (The Science Buddies website advises against choosing a warm area with access to direct sunlight.) Begin a fruit log, keeping track of the color and smell of the pieces of fruit in the paper and plastic bags, as well as any other interesting changes. Conclude your experiment when you begin noticing distinct differences between the piece of fruit in the paper bag, and the piece of fruit in the plastic bag. Determine whether your hypothesis was correct and, if desired, take pictures of the ripened fruit to include in your final project.
This experiment can be conducted in a variety of ways. For more advanced children, add different kinds of packaging to the experiment, such as plastic netting and containers, alongside the plastic and paper bags. Another option is to experiment with different brands or sizes of plastic and paper bags, or to use paper and plastic bags with and without holes. Try conducting variations of this experiment in different settings; explore how ethylene gas impacts fruit ripening when the plastic and paper bags are placed in the refrigerator versus in the sun.