Effect of Mold Growth on Various Types of Cheese

PURPOSE

The first purpose of this experiment was to compare the mold growth on Mozzarella, Colby jack, pepper jack, and cheddar cheese.

I became interested in this idea when I went to get some cheese for dinner and it had mold all over it.

The information gained from this experiment could help people decide what kind of cheese to buy for mold resistance. This would be valuable to hunters, back packers, and those who live far from a store. People who run restaurants or other big kitchens (like schools or hospitals) would also be interested. People who sell or distribute cheese would also want to know.  

HYPOTHESIS

My hypothesis was that mozzarella cheese would support the most mold growth of the three types.

I based my hypothesis on the World Book Encyclopedia article, “Cheese”, by Robert T. Marshall, “softer cheese will support more mold growth”.  

EXPERIMENT DESIGN

The constants in this study were:

• The brand of cheese
• The size of the cheese squares tested
• The temperature the cheese is stored
• The container cheese is held in during the experiment
• The type of mold used to inoculate cheese

The manipulated variable was the type of cheese. 

The responding variable was the amount of mold grown.

To measure the responding variable I used a transparent plastic grid marked with square centimeters to measure the mold growth daily.

MATERIALS

QUANTITY	ITEM DESCRIPTION
6	5cm x 5cm x 1cm of Mozzarella cheese
6	5cm x 5cm x 1cm of cheddar cheese
6	5cm x 5cm x 1cm of Colby jack cheese
6	5cm x 5cm x 1cm of Monterey jack cheese
1	Felt pen
1	Transparent plastic sheet with 1cm x 1cm grid
1	Rubber glove
1	sterilized knife
2 vials	Rhizopus stolonofer +
4	9in x 12in aluminum pans
1	Cutting board

PROCEDURES

1. Wash hands

2. Wash materials with Rubbing Alcohol 

3. Cut 4 pieces of wax paper 17cmx23cm and place in four “9inx12in” aluminum pans.

4. Cut the cheddar cheese into six slices, 5cmx5cmx1cm.

5. Put on lab coat, goggles, and rubber gloves.

6. Add water to the mold spores purchased from a biological supply house and make a mold suspension with water.

7. Dip the cheese into the mold suspension. 

8. Place cheese on the wax paper. 

9. Label the cheese slices “trial one” through “trial six”.

10. Place a 6cmx8cmx1.5cm-wet sponge in the center of each pan to avoid dehydration.

11. Cover tightly with plastic wrap.

12. Store cheese at 22 degrees in a safe place at school.

13. Repeat steps 1-8 for each of these other groups, Mozzarella, Colby jack, and Monterey jack cheese.

14. Measure the mold growth on all the cheese with the transparent grid every day for one week.

15. Record in data table.

RESULTS

The original purpose of this experiment was to compare the mold growth on Mozzarella, Colby jack, pepper jack, and cheddar cheese. 

The results of the experiment were that the highest average amount (on the final day) of mold growth was 6 sq cm on mozzarella cheese. The lowest amount was pepper jack cheese; it only had 0.3 sq cm of mold growth.

CONCLUSION

My hypothesis was that mozzarella cheese would support the most mold growth of the three types.

The results indicate that this hypothesis should be accepted; mozzarella cheese was first to mold and had the most mold growth.

Because of the results of this experiment, I wonder if the results would be different if the cheese was stored at room temperature, 3 degrees Celsius. 

If I were to conduct this project again I would have a lot more trials, run my experiment for more days, and I would use more types of cheese. I would also keep everything more accurate.

 Researched by Whitney B

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Effect of Gender on Short-Term Recall

PURPOSE

The purpose of this experiment was to compare the memory of 6th grade girls and boys when recalling a list of words.

I became interested in this idea when my math teacher said that the girls were getting better scores than the boys in our math vocabulary tests. I wanted to find out if, given the same amount of time to study the words, the results would be the same.

The information gained from this experiment could help elementary teachers teach vocabulary skills easier to younger students.

HYPOTHESIS

My hypothesis was that sixth grade girls would have better recall results than that of the boys.

I based my hypothesis on my observation of the vocabulary test results that have been given in my math class as well as my language classes during the sixth grade.

EXPERIMENT DESIGN

The constants in this study were:

- The amount of students being tested

- The amount of words to memorize 

- The order of the words in the list

- The time between when the words were given and the recall test 

- The approximate age of the students 

- The place where the test was given 

- The distance between the students during the test

- The manner students responded in writing

The manipulated variable was the gender of the students who were tested. 

The responding variable was the average number of words each gender got correct.

To measure the responding variable I counted the number of correct answers on each test and found the average for each gender.  

MATERIALS

QUANTITY	ITEM DESCRIPTION
34	quiz sheets
60	parent consent forms
16	desks
16	pencils
1	stopwatch
1	list of 20 words on overhead transparency
1	overhead projector

PROCEDURES

1. Create and hand out parent permission slips

2. Collect signed permission slips

3. Assign students into A and B groups randomly making sure that there is the same number of boys in A as in B. Do the same with the girls. 

4. Prepare test

a. Create list with 20 words appropriate for 6th graders

b. Make overhead transparency of the list with 20 words

c. Create recall response sheet 

d. Make copies of recall response sheet for all subjects

5. Prepare room for test

       a. Separate desks 100 cm apart to avoid cheating

       b. Bring group A into the testing room

6. Read instructions and answer any questions. Tell them they can quit at any time.

7. On overhead show transparency of the 20 words to memorize.

With stopwatch give the group 2 minutes to study the list of words

8. Turn off overhead and hand out response sheets and pencils

    a. Tell students to write their name on top of the test and that they            will have 5 minutes to write as many words as they can recall.

    b. Time students with stop watch for 5 minutes 

9. After 5 minutes, end the test and collect papers

10. Have students return to their class

11. Repeat steps 5-10 for group B

12. Correct the tests using the original list of words as a key.

13. Find the average answers correct for each gender 

  

RESULTS

The original purpose of this experiment was to compare the memory of 6th grade girls and boys when recalling a list of 20 words.

The results of the experiment were that the females had a better average score but the difference was very small.  The twenty-one girls had an average of 42.9% correct while the twelve boys had an average of 39.6%.

CONCLUSION

My hypothesis was that sixth grade girls would have a better score average than that of sixth grade boys when given a recall test.

The results indicate that this hypothesis should be rejected because although girls did have a slightly higher average the difference was too small for me to believe that gender affected the short-term recall results. 

Because of the results of this experiment I wonder if the student’s distance from the words affected their ability to remember the words. 

If I were to conduct this project again I would gather more subjects and make sure that all of the students could comprehend English. I would also try to even the number of boys to girls so the results were more accurate. I would stick to my schedule and make sure everyone started at the same time.

Researched by ---Mliz B

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Effect Of Propeller Pitch Angle On An Airplane Thrust.

PURPOSE

The purpose of this experiment was to determine how an airplane propeller’s angle of pitch affected thrust.

I became interested in this idea when I found out that flying an airplane costs a lot of money and if the propeller was producing maximum thrust then flying a plane wouldn’t cost as much. 

The information gained from this experiment could help pilots and the people who travel because they could get to their destination more quickly and less expensively. 

HYPOTHESIS

My first hypothesis was that the 45º pitch would provide the most thrust.

My second hypothesis was that the very low pitch (5º) would provide very little thrust.

My third hypothesis was that the very high pitch (80º) would provide very little thrust also.

I based my hypothesis on an article in the World Book Encyclopedia that said, “Each section of the propeller blades meet the air at the angle that results in the most efficient generation of thrust.”

EXPERIMENT DESIGN

• The constants in this study were:
• The airplane model
• How long the blades are
• The thickness of the blades
• The place the experiment is conducted
• How many blades on each propeller (4 blades)
• The material(s) used to make the blades
• The material(s) used to make the airplane

The manipulated variable was the pitch angle of the propeller.

The responding variable was the speed of the model airplane. 

To measure the responding variable I used a stopwatch to time the number of seconds the plane took to travel a fixed distance.

MATERIALS

QUANTITY	ITEM DESCRIPTION
1	stopwatch
1	model airplane
75-100	legos
5	tinker toys
1	meter stick

PROCEDURES

1. Make the model airplane fuselage from Legos. 

2. Make the propeller using Tinker Toys.

3. Put the wooden blades on the propeller hub.

4. Mark a line for the starting line.

5. Then measure 177.5 cm and mark a line for the finish line.

6. Using a protractor card, set all the blades at the angle that is needed for the current test: 5º, 15º, 25º, 35º, 45º, 55º, 65º, 75º, 85º

7. Put the propeller to be tested on to the model airplane.

8. Put the airplane at the starting line.

9. Turn on the airplane motor.

10. Release the airplane and at the same time have someone start the timer.

11. When the airplane gets to the finish line pause the stopwatch.

12. Record the data on the table.

13. Repeat steps 8-12, 7 more times with the same angle.

14. Then repeat steps 6-13 with the next angle. 

15. Then repeat steps 6-13 with all remaining angles.

16. Average the results for each angle.

RESULTS

The original purpose of this experiment was to determine how an airplane propeller’s angle of pitch affected thrust.

The results of the experiment were that the 15º angle went faster than any other angle. The 45º angle took more amount of time, than the 15º angle, to get to the finish line. I didn’t get up to the 85º angle because at the 55º angle it took too long to reach the finish line.

CONCLUSION

My first hypothesis was that the 45º pitch would provide the most thrust.

The results indicate that this hypothesis should be rejected because the 45º angle didn’t provide the most thrust, it provided very little thrust. 

My second hypothesis was that the very low pitch (5º) would provide very little thrust.

The results indicate that this hypothesis should be rejected because the 5º angle provided the second most thrust.

My third hypothesis was that the very high pitch (85º) would provide very little thrust also.

The results indicate that this hypothesis should be accepted because the 85º angle did provide little thrust. 

Because of the results of this experiment I wonder if a 10º angle would provide more thrust than the 5º angle, but less than the 15º angle.

If I were to conduct this project again I would do more trials than eight. I would put the airplane in the exact same spot when I started every time. I would try not to make a little push at the start so the airplane won’t go faster. I will make sure that the blades are at the right angle and that they are pushed in all the way.

Researched by --   Jalene A

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