Deflategate

Despite everything else of note that is happening in the world, it seems that we can't shake our obsession with this somewhat trivial NFL scandal that has become known as "Deflategate." So, at the risk of prolonging this discussion even further, I have decided to use this space to explore some of the scientific questions raised by this issue. Is it possible that 11 of the 12 footballs used by the New England Patriots during the first half of their 45-7 win over the Indianapolis Colts lost 2 psi naturally or did someone tamper with these balls, willfully deflating them? Certainly, it is well known that a drop in temperature will result in a loss of gas pressure. If the balls were inflated at room temperature, could the drop to the outside playing temperature account for decrease from 12.5 psi, the league-mandated minimum, to 10. 5 psi?

If we assume ideal gas behavior (a reasonable assumption under these conditions), we can determine the likelihood of a temperature-induced pressure loss quite easily. From introductory chemistry, you, no doubt, have fond memories of the ideal gas law:

PV = nRT

Here, P is pressure, V is volume, n is moles (ah, moles), R is a constant, and T is temperature. If we assume conditions of constant volume (any change in football volume is likely to be minor), pressure and temperature, in units of kelvins, are directly proportional. This means we can compute the final pressure if we know the initial pressure, initial temperature, and final temperature:

P_final = P_initial(T_final/T_inital)              (1)

Now, the game-time temperature of the Pats-Colts game was 51 degrees Fahrenheit. Because determination of the physical properties of gases requires the use of the absolute temperature scale, we will need to convert Fahrenheit to Celsius first:

(51℉ - 32)(5/9) = 11℃

Converting this to kelvins yields

11℃ + 273 = 284 K

So, the playing temperature was 284 kelvins. Let's assume that the ball was inflated initially to 12.5 psi at 80℉ or 300 kelvins. The 12.5 psi measurement is likely differential pressure, meaning that the actual pressure inside the ball is 12.5 psi plus the external atmospheric pressure (roughly 14.7 psi). The initial absolute pressure would then be

12.5 psi + 14.7 psi = 27.2 psi

When taken outside, the ball temperature will drop from 80℉ to 51℉ (300 K to 284 K). According to equation (1) above, the resulting pressure would be

Remember this is the absolute pressure. To determine the final gauge pressure, we must subtract 14.7 psi:

25.8 psi - 14.7 psi = 11.1 psi

This corresponds to a 1.4 psi loss, less than the measured 2 psi loss. So, what would the inflation temperature have to be to account for a 2 psi drop to 10.5 psi. We can compute this by rearranging equation 1.

T_initial = T_final(P_inital/P_final)

Adjusting the 10.5 psi differential pressure to an absolute pressure of 25.2 psi (after adding 14.7 psi) yields the following initial temperature:

(284 K)(27.2 psi/25.2 psi) = 306 K

This corresponds to an initial temperature of 92 ℉, a hot room, indeed, but, certainly within the realm of possibility. Of course, the officials would have to measure the pressure soon after inflation before the temperature and pressure had a chance to drop significantly.

In the end, it is certainly possible that deflation could occur naturally, but the circumstances required would be quite unusual. During recent press conference, coach Bill Bellichick suggested that the pregame preparation of the footballs may have elevated the pressures to 12.5 psi at the time of measurement, so that the game time drop may have been greater. I'm not sure what this preparation would entail, but the Patriots claim that the rules allow it.

So, did the Patriots cheat? Could the pressure drop have occurred naturally without external intervention? I won't offer my opinion. Instead, I'll let you be the judge!

What is Science?

In this exercise, I have asked my Liberal Arts Chemistry students to determine whether the "Scientific Method" as described in various science textbooks is a process typically followed by scientists. They will be posting the results of interviews with two scientists. I will summarize their findings in a subsequent blog.

Do We Trust Science?

What is the state of general scientific understanding among the U.S. citizens? Do we trust science? Adam Frank, a physics professor at the University of Rochester, wrote an op-ed piece published in the August 21, 2013 issue of the New York Times that outlines his views on these issues. You may find this essay at http://www.nytimes.com/2013/08/22/opinion/welcome-to-the-age-of-denial.html?_r=1&. What is your view. I will publish my thoughts in a later blog.

For my Liberal Arts Chemistry students, I ask that you read this essay and post your thoughts in your the blog you created for class.

What is Science?

What is science or, perhaps, more importantly, how does science progress? A rudimentary understanding of the answers to these questions is necessary to fully participate in the any debate concerning scientific issues. While, for years it has been clear to me, as a science educator, that there are many misconceptions among the general population of nonscientists regarding the very nature of science, I was finally moved to write about this after listening to a recent exchange between Horace Cooper of Project 21 and Bill Maher on the June 28, 2013 episode of HBO’s Real Time. After Maher stated that 97% of climatologists agreed that global warming existed (we may discuss the source of this number in a future blog) and that human cause was a factor, representing a clear scientific consensus, Cooper responded that the small percentage of dissenters should not be ignored. He went on to state that scientific progress occurs when an individual stands up against consensus. Mr. Cooper said, “I don’t want to hear about consensus, I want to hear about science.”  Setting aside the motives for his support of the counter prevailing view, let’s examine the validity of Mr. Cooper’s argument by asking the following questions:

• How does science progress?
• Is dissension important for scientific progress?
• May we use dissenting views as justification to refute scientific consensus?

While the nature of scientific progress has been studied extensively by philosophers of science, I will explore these questions from my perspective as a practicing scientist.

I start by examining the role of the scientist. In my view, a scientist must be an open-minded skeptic. Does this descriptor seem counter-intuitive? Perhaps. But, let's take a closer look. How does a scientist go about the task of doing science? She collects and analyzes data, developing a theory if warranted. When presented with new data or a new theory, she must be naturally skeptical, asking questions about methodology and analysis. Are the data reproducible? Are there alternative interpretations? Can new experiments be developed that test these interpretations? If the data and/or theories survive these stages of skepticism, then the scientist must be open-minded enough to accept the results as possible, even those which may contradict a currently held view. The ensuing scientific debate can be messy, but as additional data are presented that support a new theory, more scientists come to accept it and consensus is built. However, the process does not stop there; theories are constantly tested as more data are gathered. If inconsistencies develop, then the process begins anew and the old theory may be modified or rejected outright. Occasionally, an individual or small group may present a radical alternative that, while being met with resistance from the scientific community, may ultimately, through the process discussed above, build acceptance. Thomas Kuhn, noted philosopher of science, described such revolutionary developments—which have become known as paradigm shifts—in his seminal work The Structure of Scientific Revolutions. So, although scientists are human and may be resistant to change, science itself is a dynamic, anti-dogmatic process. Consensus is critical to this process because it is the best way to assess the validity of an argument. Is consensus sometimes wrong? Yes? Is the process occasionally messy? Yes. But, without consensus, how are we to distinguish between the many theories that may be presented? We cannot deny the plausibility of a theory based on personal beliefs. Hence, Mr. Cooper’s statement about wanting to hear about the science and not the consensus is fundamentally wrong; consensus is a necessary part of the scientific process.

First Posting

The notion of creating a blog to discuss science and express my views on various issues has been rolling around in my mind for years, but this is my first attempt at braving blogspace. Please bear with me as I learn the protocol and art of blogging.