Effect of Temperature on the Rate of Decomposition (J. Richard)

Research Question and Hypothesis

Strawberry Experiment - Research Question

• What is the effect of temperature on the rate of decomposition of strawberries over a ten day period of time?

Strawberry Experiment - Hypothesis

• If strawberries are placed in differing temperature conditions, room temperature and refrigerated, the strawberries at room temperature will have a more rapid rate of decomposition.

Jello Experiment - Research Question

• What is the effect of temperature on the rate of decomposition of jello over a ten day period of time?

• Does jello composition have an impact on the rate of decomposition?

Jello Experiment - Hypothesis

• If jello is placed in differing temperature conditions, room temperature and refrigerated, the jello at room temperature will have a more rapid rate of decomposition and faster rate of mold growth.

• Jello containing protein and sugar will have a faster rate of decomposition than jello containing protein alone.

***Research questions and hypotheses may differ according to students' experimental design.***

Standards

Next Generation Science Standards

• LS2.A - Interdependent Relationships in Ecosystems

• Scientific Practices:

  • Asking questions

  • Planning and carrying out investigations

  • Analyzing and interpreting data

  • Constructing explanations

  • Engaging in argument from evidence

  • Obtaining, evaluating, and communicating information

Experimental Design

Strawberry Experiment

• Students will observe the rate of strawberry decomposition at different temperatures (room temperature and refrigerated).

Jello Experiment

1. Obtain materials

2. Prepare orange jello according to the directions provided on the box.

3. Prepare the unflavored (Knox) gelatin.

   1. Obtain a bowl and a whisk.

   2. Boil at least 2 cups of water.

   3. Empty the contents of 4 envelopes of unflavored gelatin to the bowl.

   4. Add 2 cups of boiling water to the bowl of unflavored gelatin powder. Whisk until dissolved.

   5. Add 2 cups of cold water to the gelatin mixture.

4. Label 12 plastic cups as follows: OR-1, OR-2, OR-3, OC-1, OC-2, OC-3, KR-1, KR-2, KR-3, KC-1, KC-2, KC-3 (O=orange jello, K= unflavored (Knox) gelatin, R= room temperature, C= chilled, numbers represent replications)

5. Fill each of the 6 cups marked with an "O" with 1/2 cup of orange jello solution.

6. Fill each of the 6 cups marked with an "K" with 1/2 cup of unflavored (Knox) jello solution.

7. Cover all cups with plastic wrap or foil (to reduce contamination) and refrigerate for 3 hours, or until firm.

8. Remove all cups from the refrigerator and remove the foil or plastic wrap covering. Expose all samples in the same location to ambient air for 1 hour.

9. Obtain 2 large, resealable plastic containers. Label one container "Refrigerated" and the other "Room Temperature."

10. Place all cups marked with a "C" into the container labeled "Refrigerated." (There should be 6 cups - 3 orange and 3 unflavored.)

11. Place all cups marked with a "R" into the container labeled "Room Temperature." (There should be 6 cups - 3 orange and 3 unflavored.)

12. Photograph each of the two containers.

13. Place the covers on each of the containers.

14. Place the container labeled "Refrigerated" into the refrigerator. Place the container labeled "Room Temperature" into a cabinet that will be kept at room temperature. Close the cabinet door.

15. Uncover and photograph the jello every 24 hours for a total of 10 days.

***Procedures and required materials may differ according to the students' experimental designs.***

Independent variable

Strawberry Experiment

• temperature of environment (ambient room temperature and refrigerator) - measured using a thermometer

Jello Experiment

• temperature of environment (ambient room temperature and refrigerator) - measured using a thermometer

Dependent variables

Strawberry Experiment

• rate of decomposition - measured by percent covered by mold and number of strawberries affected

Jello Experiment

• rate of decomposition - measured by percent coverage by mold

• ***variables may differ based on students' experimental design***

Series

Study the rate of decomposition as a function of varying temperatures over time.

Constants and Controls

Factors Held Constant (Strawberry Experiment)

• number of strawberries

• source of strawberries

• unwashed condition of strawberries

• size and type of container

Factors Held Constant (Jello Experiment)

• type of cups used

• amount of water

• water source

• amount of jello solution in each cup

***Materials may differ according to students' experimental designs.***

Materials

For Strawberry Experiment:

• 1 box of strawberries (28 were used)

• 2 plastic containers

• refrigerator

• room temperature cabinet

• camera

For Jello Experiment:

• 1 box of orange jello (contains protein, sugar, and flavoring)

• 4 envelopes of Knox (unflavored) gelatin (contains protein)

• water

• bowl

• whisk

• 2 plastic containers

• 12 plastic cups

• plastic wrap or foil

• refrigerator

• room temperature cabinet

• camera

• additional materials may be needed, depending on student experimental design

Procedures

Strawberry Experiment

1. Obtain materials

2. Select 28 strawberries at random. Place 14 in each of the two containers.

3. Photograph the strawberries in each of the containers.

4. Place tops on each of the containers.

5. Label one container "Refrigerated" and the other "Room Temperature."

6. Place the container labeled "Refrigerated" into the refrigerator. Place the container labeled "Room Temperature" into a cabinet that will be kept at room temperature. Close the cabinet door.

7. Uncover and photograph the strawberries every 24 hours for a total of 10 days.

Jello Experiment

1. Obtain materials

2. Prepare orange jello according to the directions provided on the box.

3. Prepare the unflavored (Knox) gelatin.

   1. Obtain a bowl and a whisk.

   2. Boil at least 2 cups of water.

   3. Empty the contents of 4 envelopes of unflavored gelatin to the bowl.

   4. Add 2 cups of boiling water to the bowl of unflavored gelatin powder. Whisk until dissolved.

   5. Add 2 cups of cold water to the gelatin mixture.

4. Label 12 plastic cups as follows: OR-1, OR-2, OR-3, OC-1, OC-2, OC-3, KR-1, KR-2, KR-3, KC-1, KC-2, KC-3 (O=orange jello, K= unflavored (Knox) gelatin, R= room temperature, C= chilled, numbers represent replications)

5. Fill each of the 6 cups marked with an "O" with 1/2 cup of orange jello solution.

6. Fill each of the 6 cups marked with an "K" with 1/2 cup of unflavored (Knox) jello solution.

7. Cover all cups with plastic wrap or foil (to reduce contamination) and refrigerate for 3 hours, or until firm.

8. Remove all cups from the refrigerator and remove the foil or plastic wrap covering. Expose all samples in the same location to ambient air for 1 hour.

9. Obtain 2 large, resealable plastic containers. Label one container "Refrigerated" and the other "Room Temperature."

10. Place all cups marked with a "C" into the container labeled "Refrigerated." (There should be 6 cups - 3 orange and 3 unflavored.)

11. Place all cups marked with a "R" into the container labeled "Room Temperature." (There should be 6 cups - 3 orange and 3 unflavored.)

12. Photograph each of the two containers.

13. Place the covers on each of the containers.

14. Place the container labeled "Refrigerated" into the refrigerator. Place the container labeled "Room Temperature" into a cabinet that will be kept at room temperature. Close the cabinet door.

15. Uncover and photograph the jello every 24 hours for a total of 10 days.

***Procedures and required materials may differ according to the students' experimental designs.***

Sample data and graphs

Include raw data and graphs. Make certain to include units in all measurements, titles on all graphs, and labels on all axes.

Analysis & Conclusions

Strawberry Experiment

• The rate of decomposition was significantly higher in the trial at room temperature, in comparison to the refrigerated strawberries.

Jello Experiment

Photos & Movies

References

Moldy Jello Instructions