Biodegrading In The Wildlands-Can You Dig It

Description: The purpose of this experiment is to examine the effects of biodegradation. This exploration involves burying different items in the school yard and then examining the changes that take place. Through this examination you can determine which materials are more and less biodegradable.

Grade Levels: 4-12 (Note: This experiment can be simplified or made more challenging depending on the developmental levels of your students. See Teacher Information.)

Approximate Time Involved: 45 minutes to organize groups, collect equipment and bury materials, 60 minutes to dig up materials and analyze results

National Science Standards Addressed:

Content Standard A: As a result of activities in grades K-12, all students should develop

Abilities necessary to do scientific inquiry
Understanding about scientific inquiry

Program Standard D: The K-12 science program must give students access to appropriate and sufficient resources, including quality teachers, time, materials, and equipment, adequate and safe space, and the community.

Good science programs require access to the world beyond the classroom.

Teacher Information:

If the ground is hard and dry, it will make it easier for you students to dig a hope if the study area is watered a day or two before the experiment is to begin.

Schoolyards, fields, woodlands, and parks provide students with a great opportunity to examine the effects of biodegradable and non-biodegradable products upon the Earth's environment. Note: Encourage your students to search the Internet and other sources for more information about biodegradability.

This should become a team exercise where your student groups might each develop and write using the scientific method as their model. This will also replicate the real world challenges facing a research scientist.

Challenging Your Students to Be Problem Solvers:

To make this experiment more challenging you may wish to have your children pose problems with the experiment (give hypothesis for the experiment if they were to put items in different locations). This should become a team exercise where your student groups might each conduct Internet research on biodegradable items and what is currently happening with our environment concerning non-degradable items.

Needed Materials: One flat 10 x 10-cm piece of the following: one 10" plastic plate, one 10" foam plate, one 10" paper plate (no wax), cardboard (ex. Cereal box), heavy duty aluminum foil, clear plastic acetate grid (made with centimeter graph paper copied on acetate). Also needed: one peg with brightly colored top, hand spades, garden shovel, metric ruler, marker

Safety Rules: Hand spades and shovels are sharp. Be careful with them to avoid cuts. Be sure to wash your hands because when you finish you may have soil bacteria on them.

Procedure:

Student Information: You will be working in teams of four. Your team is responsible for finding out which sample is the most biodegradable in the 14 day test period. This experiment will be set up in the first session and finished 14 days after the samples have been buried.

Procedural Steps for Conducting the Investigation

1. Locate an area where the samples will be buried. This area should be at least 3 yards from other class groups.

2. Dig a 30 x 30-cm square hole that is at least 10 cm deep.

3. Place the samples in the hole so that they are not resting on top of each other.

4. Cover the samples with soil.

5. Place a marker with a brightly painted top in the soil over the samples so that you can find it when it is time to dig up the samples.

6. 14 days after the samples have been buried, return to the site and carefully dig up the samples.

7. Carefully place the samples on a tray or in a box lid to carry them inside. Note: The samples may be brittle and tend to fall apart.

8. Place a 10 x 10-cm clear plastic acetate grid over the sample and secure it with a paper clip.

9. Use a marker to color the grid over any area that shows that it is changing or breaking down.

10. When you finish coloring, count the squares and record the number in a chart.

11. Create a chart and graph of the data.

Below is a list of questions that can be used to stimulate student discussions. If your students are at a developmental level where you are able to challenge their higher level thinking skills, then only present them with the first set of questions from each group below. Use the second list of questions as a way to stimulate thinking when you students seem unable to expand their knowledge on their own.

Examining Results

Discussion Questions that Require More Critical Thinking Skills:

What were your conclusions for this experiment?
What could you infer based on your conclusions?
How would you design this experiment differently the next time?

Discussion Questions that Require Less Critical Thinking Skills

Did your results match those of other collaborative teams?
If your results were different, what do you think might have been the reason?
Did the outside temperature have any impact on biodegradability?

Examining Local Results

Discussion Questions That Will Require Critical Thinking Skills to Compare Local Data to that of Others

How did your results compare with the results of others?
What conclusions can you make when you compare your results with the results of others?
What inferences can you draw from your additional conclusions?
What changes would you now make in this experiment based on the information you now have?

Conservation Links

Environmental Inquiry - Biodegradation Here a brief description of what biodegradation is.

Biodegradable Polymers This is a short article that expresses the importance of biodegradable polymers.

Biodegradable Crayons From Soybean Oil This is an interesting article to show your students an example of how companies want to make their products biodegradable. See what other products your students can find by searching the web.

Composting in Schools At this site you will find information about the science of composting and ideas for research projects.

The Compost Research Page This webpage provides links to sites that provide information about different composting techniques. An interesting subject to look at is vermi-composting.