Method

Materials

1. A graduated cylinder to measure the water
2. A thermometer
3. Life brand portable instant cold pack
4. Timer
5. Notebook to record temperatures and data
6. Triple beam balance to weigh each of the fertilizers
7. Measuring cup
8. Ziploc resealable sandwich bags
9. No name brand resealable snack bags
10. Scissors
11. CIL Golfgreen 12-3-18 fertilizer
12. CIL Golfgreen Premium Weed and Feed 28-4-8 fertilizer
13. Scotts Turf Builder 31-3-8 Pro Lawn Fertilizer

Procedure

1. Cut and then open the Life brand instant portable cold pack.
2. Take the ammonium nitrate from inside the cold pack and weigh it, in grams, using the triple beam balance.
3. Then with a graduated cylinder, measure the amount of water, in milliliters, in the cold pack.
4. Follow the instructions that are written on the Life brand instant cold pack. Squeeze down from the top of the bag using both hands to pop the inner fluid bag. Shake the bag briefly to mix the ammonium nitrate with the water.
5. With a pair of scissors make a small incision on the side of the cold pack.
6. Insert the thermometer in the cold pack through the incision and then record the temperature of the cold pack for 20 minutes in a notebook.
7. Measure the same amount of grams (140 grams) as in the cold pack of each of the three fertilizers and put each fertilizer in a separate resealable snack bag. Then seal the bag.
8. Take the same amount of water, in milliliters, and place it in a Ziploc sandwich bag.
9. Place the snack bag in the sandwich bag and seal this bag.
10. Carefully unseal the snack bag, which is inside the sandwich bag, and shake the bag briefly in order to mix the fertilizer with the water, as was done with the instant cold pack.
11. Make a small incision on the side of the sandwich bag.
12. Insert the thermometer in the small incision and place the mercury end of the thermometer in the mixture of fertilizer and water.
13. Then record the temperature of the homemade instant portable cold pack for 20 minutes in the notebook.
14. Repeat this process with 100 grams of the most effective fertilizer and 100 milliliters of water. Do the same with 120 grams of this fertilizer and 120 milliliters of water. 
15. Calculate the number of grams of nitrogen found in ammonium nitrate. Then calculate what percent of the ammonium nitrate this represents.
16. Using this percentage, calculate how many grams of nitrogen exist in the ammonium nitrate in the cold pack.
17. Calculate the number of grams of nitrogen in each of the three fertilizers that will imitate the percentage of nitrogen in the cold pack.
18. Place each of these fertilizers in three separate Ziploc sandwich bags.
19. To keep imitating the conditions of the cold pack, mix each of these fertilizers with the same amount of water as in the cold pack.
20. Repeat procedures 10-13 inclusive for these three packs.
21. Calculate the cost of each of the packs formed and compare the costs with the cost of the Life brand portable instant cold pack.

Compare the temperatures of each of the packs formed.