Explore what students will learn and check out the additional resources that go along with the labs. Check out our professional development opportunities to learn how to receive free training and supplies for this lab
Plastic has shaped the world in ways that we could have never imagined. The importance of plastic in the modern world cannot be understated. Plastic is inexpensive, light- weight, and durable and can be molded into virtually any shape. Plastic is present in every aspect of our lives and largely responsible for the advancements in society that we take for granted each and every day.
Still, plastic has its drawbacks. Most plastic is manufactured from nonrenewable petroleum. It is so durable that it will take generations before it biodegrades. Single-use plastic products are commonplace because they are inexpensive and convenient. Plastic trash is becoming a global concern, and microplastics are even now showing up in the food chain.
An alternative product that has all the characteristics of petroleum-based plastic, but is made from a renewable, biodegradable resource, is in high demand. Plastic made from corn is one possible alternative. There are currently a multitude of plastic products being produced from corn and more are being developed each day.
This lab lets your students create a plastic polymer from cornstarch. Students can then adjust the quantities and proportions of each chemical to create plastics with different properties. Students can then try to come up with a practical, real-world application for the type of plastic they develop.
Students who demonstrate understanding can:
Students should wear safety googles at all times during this activity. Students should also follow all class guidelines for using a hot plate safely and use appropriate safety equipment for handling hot glass and other hot materials. Lab coats or aprons should be used when heating the corn plastic in case of splattering.
Length of Time for Preparation: 20 minutes
Length of Time for Classroom Teaching: 2-3 class periods
Set up your lab stations. Each lab station should include all materials necessary for each group to complete the lab.
Plastic is a material consisting of any of a wide range of synthetic or semi-synthetic organic compounds that are malleable so it can be molded into solid objects. Plastics are typically organic polymers of high molecular mass and often contain other substances. They are usually synthetic, most commonly derived from petrochemicals; however, they can be made from renewable materials such as corn or cellulose from cotton.
In this lab:
Introduce the topic and assess students for prior understanding.
Let students discuss their ideas, and guide the discussion without telling them if they are right or wrong.
This lab can be differentiated to fit a variety of student levels and classroom needs.
Class Period 1
After your class discussion, show them the plastics made from corn. Ask them which items they think were made from corn. Tell the students they will be able to make a type of plastic from corn. This will not be the same type of plastic used to make the cups and spoons but a polymer that can be safely made in a middle school lab.
Mix in glass bowl:
Stir and heat on medium until the mixture becomes clear. Put the corn plastic in a plastic bag for immediate examination. The corn plastic can be put into molds to make a shape, then store overnight.
Class Period 2
Have each group examine their plastic they made from the previous class period. Have them discuss the properties of their plastic.
The next goal is to see how each material affects the properties of the plastic. Assign each group a different component of the corn plastic:
Group 1 an amount of water
Group 2 an amount of glycerol
Group 3 an amount of cornstarch
Group 4 an amount of vinegar
Group 5 adding a drop of corn oil
Group 6 adding a drop of food coloring
Have the student groups make 2-4 different batches of corn plastic. Each batch should contain an incremental amount more or less of their given material. The teacher can assign the amount of materials to be changed, or the teacher can allow the students to make that decision. All other proportions of materials should stay the same.
Example: How does increasing the amount of cornstarch by 1 tbsp. affect the properties of the corn plastic? How does decreasing the amount of cornstarch by 1 tbsp. affect the properties of the cornstarch?
Put the corn plastic in a plastic bag for immediate examination. The corn plastic can be put into molds. If you want the students to make a shape, then store in plastic bags overnight.
Class Period 3
Have each group examine their plastic they made from the day before. Have them discuss the properties of their plastic. Share with the class how the properties differed from the original procedure.
Using what they have learned, challenge the groups to create a new corn plastic. An example of a challenge could be: develop a corn plastic that can be molded and retain its shape. Have students keep track of exactly what proportions are used in each new batch created. The plastic can then be placed in a mold and allowed to dry overnight.
Tip:
Don’t add food coloring until after the mixture becomes clear during the heating process. If you add the food coloring earlier, you will not be able to determine when the plastic turns clear and has finished heating. Cut up the plastic ice cube trays into individual molds.
Resources:
Corn plastic can be compared to other types of polymers that can be made in the classroom. Properties used to compare polymers include but are not limited to: stretchiness, bounciness, stickiness and density.
Students should look for advantages and disadvantages of making plastic out of renewable/biodegradable sources compared to plastic made from fossil fuels.
Challenge students to come up with a real-word application for their corn plastic based off of the unique properties of each batch created.
Take it Further
Have students see if they can compost the plastic and find out if and how long it takes to biodegrade. Consider setting up an experiment within your school to find results.
Have students research the current products being made from corn plastic. Use the research to write a letter to corporations, such as fast food chains, that use non-biodegradable plastics and persuade them to switch to corn-based plastic products.
Kansas Corn funds research at Pittsburg State University that is replacing non-biodegradable products with corn. Products include flame-retardant insulation for homes and rechargeable batteries. For more information, contact Ram Gupta.
Note: To learn more about agriculture careers, visit https://agexplorer.ffa.org/.
https://science.howstuffworks.com/environmental/green-science/corn-plastic.htm
https://www.acs.org/content/dam/acsorg/education/resources/highschool/chemmatters/videos/chemmatters-april2010-bioplastics.pdf
https://www.instructables.com/id/DIY-Bio-plastics/
Any educator electing to perform demonstrations is expected to follow NSTA Minimum Safety Practices and Regulations for Demonstrations, Experiments, and Workshops, which are available at https://static.nsta.org/pdfs/MinimumSafetyPracticesAndRegulations.pdf, as well as all school policies and rules and all state and federal laws, regulations, codes and professional standards. Educators are responsible for abiding appropriate legal standards and better professional practices under a duty of care to make laboratories and demonstrations in and out of the classroom as safe as possible. If in doubt, do not perform the demonstrations.
Investing in Kansas teachers and students is a priority for the Kansas Corn Commission. We are committed to providing materials and training to support STEM education while fostering an understanding of how corn farming and agriculture fit into our daily lives. Professional development workshops are offered to teachers seeking to expand their knowledge and inquiry-based teaching skills. Workshop participants receive free lab supplies needed for the lessons.
This lesson is the work product of the Kansas Corn Commission. Our lessons are written in collaboration with Kansas teachers for use in the classroom. Teachers may copy and share this curriculum. Use of this product for commercial or promotional use is prohibited without express permission of Kansas Corn.
As the need to produce more food with less resources grows, it is important that future generations have a better understanding of agriculture and how corn farming and agriculture fit into our daily lives. That’s why the Kansas Corn STEM program provides lessons to teach science through the lens of corn. We are committed to providing free materials and training to support educators.
