1. The Effect of Heat on Enzyme Activity By: Kelly Duffy, Grade 9.

2. Problem How hot does it need to be for pineapple enzymes to stop working?

3. Research Enzyme A catalyst can be used over and over again in a chemical reaction: it does not get used up. Enzymes are very much the same except that they are easily denatured by heat. Denature All enzymes are made of protein; that is why they are sensitive to heat, pH and heavy metal ions.

4. Hypothesis If the pineapple enzymes are heated to 37° Celsius, then they will stop working and won’t be able to melt the jello.

5. Materials A scale One fresh pineapple Two boxes of jello mix A candy thermometer A tray A pot 24 dishes

6. Procedure Room was 23 degrees Celsius. Experiment was not interfered with. Two packets of jello mix were poured into a 22 by 33 cm glass pan. 236 milliliters of boiling water were poured into glass pan. Solution was stirred for two minutes. 236 milliliters of cold water were poured into glass pan. Solution was stirred for a minute. Glass pan was placed in refrigerator at five degrees Celsius for four hours to jellify. The jello was cut into 3cm slabs. Pineapple was cut into 1cm cubes; core was excluded. Twenty-four cubes in total.

7. Procedure Initial temperature of water taken; 23.5 degrees C. Dishes labeled at 5-degree increments after 23.5°C. Pineapples placed in pot of water and put on low heat. Pineapples taken out at 5-degree increments. Pineapple cubes cooled for thirty-five minutes. Pineapple cubes placed on jello slabs. The first 13 pineapple cubes melt jello completely. The next four only melt part of the jello. The pineapple cubes stopped melting the jello after being heated to 103.5 degrees C.

8. Variables Independent variable: The temperature of the pineapple cubes. Dependent variable: Whether or not the enzymes are working. Control: The pineapple that hadn’t been heated. Constants: Pineapple, jello.

9. Data

10. Conclusion Hypothesis: If the pineapple enzymes are heated to 37° Celsius, then they will stop working and won’t be able to melt the jello. The hypothesis was not supported. The enzymes stopped melting the jello after being heated to 103.5° Celsius. The experiment could be improved by testing the effect of heat on the enzymes of many fruits.

11. Thanks To… Those in attendance listening Works Consulted http://www.education.com/science-fair/article/effect- of-heat-on-enzyme-activity/ http://www.education.com/science-fair/article/effect- of-heat-on-enzyme-activity/ http://www.wordiq.com/definition/Enzyme http://www.purchon.com/biology/enzymes.htm Any Questions?