DuPont Challenge Science Essay Competition
Conserving Earth’s Endangered Helium
by Michelle Woods
Waubonsie Valley High School
Sponsoring Teacher: Ray Piccininni
First place, junior division, 2011
Imagine a world in which doctors cannot use MRIs to diagnose patients health problems. Now imagine a world in which a 5-year-old girl cannot have pink balloons floating at her princess themed birthday party. Both of these scenarios could soon become a reality because there is currently a worldwide shortage of helium due to the variety of important uses for this nonrenewable natural resource (Jones, 2002). Applications which include purging fuel tanks in rocket engines, cryogenics (the study of matter at low temperatures), and cooling superconductivity magnets in MRIs all use liquid helium (National Research Council of the National Academies, 2010). In 1960, the government established the Federal Helium Reserve which contains the worlds largest supply of helium (Tamura, 2010 and Federal Helium Program, 2010). This helium is predicted to be depleted in the next 20–30 years (Tamura, 2010). Scientists need to find ways to make the helium supply last longer. However, finding alternative substances to use in place of helium is difficult because liquid helium is the coldest known substance on Earth with a boiling point of 268.9◦ C (Compressed Gas Association, Inc ., 1990). Conserving what is left of the helium is an easier way to ensure that the supply will last longer. One way to achieve this is to find alternative ways to inflate decorative balloons so that helium can be conserved for more important applications and will continue be available for future generations.
I first became interested in this problem a couple of years ago when my dad, who works for an industrial gas company, showed me an article explaining how engineers were attempting to recapture the helium used in those enormous Macys Thanksgiving Day Parade balloons instead of allowing it to escape into the atmosphere (Linde Gas LLC, 2008). Since 7% of the worlds helium is used to inflate balloons (Pacheco, 2008), researchers at my dads company had a different idea that would help to conserve helium. The plan was to mix nitrogen with helium to inflate balloons to have at parties and celebrations. Why use nitrogen to mix with helium you may ask? To begin with, nitrogen makes up a major portion of the atmosphere and is a component of gases found in springs, volcanoes, and mines (Fleishman, 2009). Thus nitrogen is abundant and easy to get, unlike helium, which is formed from elements in radioactive rocks that break down and is only found in natural gas fields in a few places such as in Texas, Wyoming, Oklahoma, Saskatchewan, Poland and around the Black Sea (Liebeskind, 2009 and National Research Council of the National Academies, 2010). Furthermore, nitrogen and helium are both inert gases and will not react with each other. In other words, when these two gases are mixed together they will not create an explosion or harmful gas. At this point you may be wondering how a balloon inflated with a helium nitrogen gas mix is going to float. Well, nitrogen has a density of 1.153 kg/cubic meter, which is slightly less than that of air which is 1.2 kg/cubic meter. Helium only has a density of 0.165 kg/cubic meter (Compressed Gas Association, Inc., 1990). Even though nitrogen makes up 78.08% of the air we breathe (Newton, 1999), when nitrogen is mixed with helium the balloons should still be able to float because both helium and nitrogen are less dense than air. However, too much helium cannot be replaced with nitrogen because then the balloons will not contain enough helium to overcome the affects of the higher density of nitrogen. Due to its properties and availability, nitrogen is a gas that works well with helium. Therefore, why not try to develop a mix that will allow balloons to float for an acceptable amount of time so that helium can be conserved for important scientific and medical purposes.
I decided to design an experiment to test this idea because conservation of Earths natural resources is critical for future scientific work. The purpose of my experiment was to determine the amount of helium that can be replaced with nitrogen such that latex balloons filled with a helium nitrogen gas mix stay in the air at least 90% as long as latex balloons filled with 100% helium. The gas mixes used for the experiment included 90% helium, 10% nitrogen; 85% helium, 15% nitrogen; and 80% helium, 20% nitrogen. The results from 32 trials showed the minimum concentration of helium which can be used in balloons so that they float at least 90% as long as balloons filled with pure helium is 85%. The average time the helium filled balloons stayed in the air was approximately 17 hours, while the average float time for balloons containing 85% helium mixed with 15% nitrogen was about 15 hours. As one can see there was not a considerable difference in how long the two sets of balloons floated. For this reason, people can fill balloons to have at parties and events with an 85% helium, 15% nitrogen gas mix and expect the balloons to last for the duration of the special event.
It is important to be aware of the helium shortage and to strive to conserve what is left of this nonrenewable natural resource. If society continues to use helium unnecessarily for
balloons, there will not be enough left for applications that are more important. We can still brighten a friends birthday with a beautiful balloon bouquet and continue to use balloons to celebrate special occasions, but consumers should use helium mixed with nitrogen to inflate these balloons so that more helium will be available for future generations. Conserving helium through the use of a helium nitrogen gas mix may require a change in expectations for how long balloons float; nevertheless, this small change can make a significant impact on the amount of helium available for future scientific and medical purposes.
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