An alternative for liquid nitrogen and its effect on objects

 

 By: Diego De La Guerra

Writing for Engineering

February 24, 20

Abstract

   Liquid nitrogen is known for its extreme low temperature and effect on materials. An alternative can be used in its place because liquid nitrogen is not always simple to locate. In this option, liquid acetone and dry ice are combined to create a supercooled liquid. It is believed that when placing various objects into the alternative cooled liquid, it will cause the same effects, as if it would if placed in liquid nitrogen. In order to prove that it can serve as an appropriate alternative, the temperature of the dry ice combined with acetone was examined to test its ability to freeze various objects. To do this, pieces of dry ice were placed inside a glass bowl surrounding a plastic cup with holes, to allow the acetone to freely move inside and out. This was now a bath of freezing acetone and various objects were placed inside the cup for a few minutes to check its condition. The results showed that these objects did in fact freeze, just like how they would in liquid nitrogen. 

Introduction

   Liquid nitrogen is created when nitrogen molecules are in a liquid condition. With a temperature of -320 degrees Fahrenheit, liquid nitrogen is recognized as one of the most icy substances. Liquid nitrogen is dangerous because of its temperature, which can cause it to freeze whatever it comes in touch with, including living tissue and other materials. Liquid nitrogen is distinct from other liquids due to its temperature. In the event that liquid nitrogen is difficult to find, there is another option. By combining dry ice and liquid acetone, we can test to see if it has the same effects as liquid nitrogen. The dry ice alone has a temperature of -109.3 degrees fahrenheit and acetone cannot freeze entirely until -139 degrees fahrenheit. Therefore, by mixing both we can maintain a liquid state with the same temperature as dry ice. By doing this experiment, it is believed that when placing various objects into the finished cooled liquid they will freeze, just like how it would if placed in liquid nitrogen. 

Methods/Materials

•  Dry ice cubes
• Acetone
• Gloves
•  Glass bowl
• Plastic cup 
• Drill 
• Hammer 
•  Carrot 
• Rubber Band Ball 

   Firstly, using the drill, drill a few tiny holes all around the plastic cup and place it in the center of the glass bowl. The acetone will flow in and out of the cup at this point, keeping room inside of the cup for the objects to be placed in. Secondly, using the hammer, break up the large chunks of dry ice into smaller pieces and scatter them around the plastic cup inside the glass bowl. Then begin pouring the acetone around the cup and then inside. Bubbling should occur. To check if the acetone is cold, place only the tip of your index finger with the glove inside the cup, and you should see that the glove becomes stiff. Next, grab the carrot and only place the bottom part into the cup and watch it boil for 1 minute. Repeat this step with a rubber band from the ball, and then the whole ball itself. After taking the objects out of the cooled acetone, use the hammer to smash a dry carrot and the cooled carrot to compare the way it shatters, as well as the rubber band ball. With the single rubber band, pull it apart to check if it still stretches out easily.

Results

  After taking the carrot out of the acetone, the bottom portion was frozen and sounded like metal after hitting the table a few times. The carrot was shattered as if we were smashing ice cubes into little pieces. As soon as the single rubber band was taken out, the rubber band broke instantly after being pulled apart. A rubber brand usually stretches in warm temperatures, but in this case the rubber band was not able to stretch out easily. Therefore, after taking out the entire rubber 

band ball out of the cooled acetone, the ball was dropped and it sounded exactly like a rock. However, the smashed rubber band ball was still in its form as a result of how hard it was, with only small pieces of rubber band being broken off.

Discussion

  After witnessing the way each object felt and the way they were shattered, we concluded that the combination of dry ice and acetone is an appropriate alternative for liquid nitrogen. Therefore, the hypothesis was supported. Although liquid nitrogen has more of a low temperature, the dry ice aided in making the acetone as cold as possible, which froze each object. There was a significant difference between the objects in their dry stage and after they were cooled by the acetone. 

Conclusion

  Overall, this experiment demonstrated the effects of dry ice and acetone on various objects to prove that it can serve as an alternative for liquid nitrogen. Although liquid nitrogen has a lower temperature than the dry ice, the objects used in this experiment were still able to freeze in cold acetone as well. It was discovered that acetone was not able to freeze to a solid form due to the temperature of dry ice. For acetone to freeze it needs to be cooled at a temperature of -139 degrees fahrenheit, which is not the same temperature as dry ice. This meant it would maintain its liquid state just like liquid nitrogen and still cause the same effects towards the objects that come in touch with the supercooled liquid. 

 

References

The King Of Random. (2018). What Does DRY ICE Do in a Metal Foundry? TKOR’s Best Dry Ice Experiment: Burn? Melting? Smoke? https://youtu.be/a5g6W5a9_Bo