Milk, Juice, Carrot Lab

Milk

Introduction: The purpose of this experiment is to find out what will happen to milk that is left at room temperature for 4 days.

Hypothesis:  A ½ cup of milk left out in room temperature for 4 days will develop a sour smell and will curdle.

Procedure: I poured ½ cup of cold whole milk into a 1 1/2 cup glass mason jar. The milk was poured into the mason jar as soon as I took it out of the refrigerator. I then set the mason jar behind my kitchen sink for four days. 

Results: The milk smelt a little off but not sour like I had expected it to. The milk did not curdle as much as I thought it would. There was a slight ring around the glass and it had just begun to curdle on the bottom.

Day 1

Day 2

Day 3

Day 4

Day 4 

Conclusion: I think that the reason the milk did not sour and curdle is because it was not in a warm enough spot. Milk contains bacteria that grow by changing the lactose sugar into lactose acid. When the bacteria changes the sugars into acid the souring and curdling happen. (Kagan) This happens when milk becomes old or when it is in warm temperatures. I think if I had kept my milk in a different spot or performed this experiment in the summer my hypothesis when have been proved.

Juice

Introduction: The purpose of this experiment is to see how the molecules in water react when cranberry juice is added to the water. This will be done three times. The first time will be room temperature water, the second will be ice water and the third will be boiling water.

Hypothesis:  A ½ cup of juice poured into ice water, room temperature water or boiling water will mix easily with the water.

Procedure: I measured 1 cup of tap water and placed it in a glass. Then I measure ½ cup of room temperature cranberry juice. I poured the cranberry juice into the water and watched the reaction. Next I placed 5 ice cubes into a measuring cup then added water until it measured 1 cup. I placed the 1 cup of ice water into a glass and added ½ cup of room temperature cranberry juice to it. Then I measured 1 cup water and poured it into a glass. I heated the water to boiling in the microwave. Then I added ½ cup of room temperature cranberry juice to it.

Results: You could see the cranberry juice mixing with the water when it was poured into the tap water. It traveled down and then began to spread until it was equally mixed.  When the juice was poured into the ice water, the result was the same. I could see the cranberry juice moving in the water as it was mixing together. I could hear the ice cubes making a cracking sound and it seemed to mix a little slower than with tap water. When the juice was poured into the hot water that had been boiling, the water began to bubble a little again. The juice also appeared to move faster through the water and mix faster.

Juice added to room temperature water

Juice added to ice water

Juice added to boiling water 

Conclusion: The juice did mix easily with the water in all three experiments. It mixed the fastest with hot water and the slowest with cold water. The reason the juice mixed faster with the hot water is because the molecules in hot water move faster than in cold water. Also they are further apart so the juice was able to mix faster. The molecules in cold water are closer together so the juice mixed a little slower. (Kessler, Galvan and Boyd) So my hypothesis was correct in that the juice mixed easily, however it mixed the easiest with boiling water.

Carrot

Introduction: The purpose of this experiment is to determine what will happen to a carrot soaked in salt water for 24 hours and what will happen to a carrot soaked in water for 24 hours.

Hypothesis: A cut carrot placed in water will stay the same size after a period of 24 hours. A cut carrot placed in salt water will begin to wilt after 24 hours.

Procedure: I filled a glass mason jar with 1 and ½ cups of water. I added one teaspoon of salt and labeled the jar salt water. I cut a carrot in half and measured the length and width. The length was 4 1/8 inches and the width was 7/8 inches. I tied a piece of string tightly near the end that had been cut then placed it in the salt water with the cut side down. I filled up another mason jar with 1 and ½ cups water. I labeled that jar fresh water. I cut another carrot in half and measured the length and width. The length was 3 6/8 inches and the width was 7/8 inches. I tied a piece of string tightly near the end that had been cut then placed it in the fresh water with the cut side down.

Results:  I removed the carrot from the salt water 24 hours later. When I checked the string it was a little loose and I was able to easily slip it off. The carrot was easy to bend. It was flexible and rubbery. The end that had been cut felt a little slimy. The measurements were about the same with the length being 4 1/8 inches and the width just a tiny bit less, maybe 13/16. I then took the carrot from the fresh water. The string was very tight. The cut side didn’t feel any differently and the carrot was very firm and I was not able to bend it at all. The measurements were the same, the length was 3 6/8 inches and the width was 7/8inches.

Conclusion: The carrot in the salt water became flexible due to the water inside the cells moving out of the carrot. The water was moving out in an attempt to “equalize the water inside and outside of the carrot.” (Drane, Eppich and Ruch) The carrot placed in fresh water should have the opposite happen, the water will move into the cells in the carrot. My hypothesis for the carrot placed in salt water was correct. My hypothesis for a carrot placed in fresh water was not.

Carrots soaking

After soaking for 24hours. Strings already removed. 

Works Cited

Drane, Carol Ann, Lois Eppich and Mary Lee Ruch. Find another Lesson Plan? . n.d. 11 Feburary 2012 <www.create.cett.msstate.edu/cosee/cosee-lplan_view.asp?articleID=15>.

Kagan, Mya. Why does milk get sour? . n.d. 9 February 2011 <http://whyzz.com/why-does-milk-get-sour>.

Kessler, Jim, Patti Galvan and Adam Boyd. Middle School Chemistry. 2012. 12 February 2012 <http://www.middleschoolchemistry.com/faq/#authors>.