Nature or Naughty Instructor s Notes (Including Student Worksheets and Sample CERs)

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1 Nature or Naughty Instructor s Notes (Including Student Worksheets and Sample CERs) Elizabeth Megonigal, Huntingtown High School, Science Department, Huntingtown, MD Introduction to the Deflategate Controversy The National Football League (NFL) began as the American Professional Football Conference in 1920 and has grown to become the most popular sports league in the United States. It includes 32 teams divided equally between the American Football Conference (AFC) and the National Football Conference (NFC), with each team playing 16 regular season games, followed by the playoffs, and culminating with the grand spectacle of the Super Bowl game between the AFC and NFC champions. 1,2 The AFC playoff game is where the 2015 Deflategate drama and Tom Brady s troubles begin. On January 18th, 2015, the New England Patriots squared off against the Indianapolis Colts in the AFC Championship at Gillette Stadium, Foxborough, MA. During the first half of the game, the Colts staff approached game officials with suspicions that the Patriots were using underinflated footballs. This led officials to check the pressure of the footballs being used by both teams at half-time. Using two different pressure gauges, officials found that all 11 of the Patriots footballs were underinflated, meaning <12.5 pounds per square inch gauge pressure (psig), whereas the four footballs of the Colts they tested were within the accepted pressure range of psig on at least one of the two pressure gauges used for the study. At that time, the referees filled the Patriots balls to the proper pressure, and the game concluded uneventfully with a convincing win by the Patriots, The media immediately began to speculate as to the cause of the underinflated footballs. Detractors suspected deliberate tampering with the balls pressure, while supporters reasoned it was merely a result of the cold field conditions that day. 6 In an effort to quell these suspicions, the NFL announced that they had hired an independent law firm, Paul, Weiss, Rifkind, Wharton and Garrison (PWRWG), to lead an investigation. PWRWG assembled an investigative team that included Exponent, a USA scientific and engineering consulting firm, and Daniel Marlow, professor of physics at Princeton University. And so the investigation and data collection began. Investigation Tests and Findings The following background information was taken directly from the Wells Report, inclusive of the Exponent s Report as an appendix. It is helpful in leading and guiding the discussion, and gives the activity credibility as a scientific exercise by having student engage in the science practices while analyzing authentic data. Physical factors that Exponent (the scientific and engineering firm investigating the case) tested included the following. a. The impact of game use on ball pressure- Performed load test of 650 lbs/sec for 1000 cycles and found it did not to affect the ball pressure (pg 32of appendix) b. The impact of repeated insertions of an inflation needle into the football- Based on the information provided by referees, it is most likely that each ball was tested three times. 1

2 The investigation showed a loss of 0.01psig/needle insertion. Therefore, they concluded that the pressure change was not significant. (pg 35 of appendix) c. The natural leak rate and permeability of properly functioning footballs- The permeability tests found the balls were functioning properly and no significant loss was detected. (pg 33 of appendix) d. The relative humidity of the air in the room(s) in which the footballs were inflated- Tested using humidity chambers and found to have no significant effect on pressures. (pg 36 of appendix) e. Variation of the volume of the footballs- Tested the volume of the footballs using a high resolution laser scan (pg 37 of appendix) at the various relevant pressures (10.5 to 13.5 psi) and moisture conditions and found that the volume of the ball was constant. (pg 197 of Wells Report) In addition, the volume of an NFL football was found to be 4.24 L. f. The different treatments used by the Patriots and the Colts to condition the surface of the balls prior to the game, such as the vigorous rubbing described by the Patriots as a step in the process used to break in their footballs. Tested using an infrared camera and found that rubbing increased the pressure slightly, but it returned to normal after 30 minutes. (pg 33 of appendix) The report concluded that no combination of these factors was sufficient to explain the lower than expected pressure of the Patriot s footballs. Pressure Gauge Accuracy: Although the two pressure gauges used read differently, they both read consistently. 2

3 Available Data for Students from Wells Report Ball Pressure Data a. Initial pressure of Patriot s balls was 12.5 psig. b. Initial pressure of Colt s balls was 13.0 psig c. At half-time in the Official locker room, the Patriot s balls were measured first and then Colt s ball. d. Two gauges were used to measure the balls pressures at half-time (Non-Logo and Logo brand) e. It is unclear which gauge was used at pre-game check, but it was most likely the Non- Logo gauge (the gauge that reads lower). (Tested by scientific team.) f. Below are the pressures of the footballs for both teams measured at half-time in the Officials Locker Room. Patriots Ball Blakeman (Ref #1) (psig)* Prioleau (Ref #2) (psig) Colts Balls Blakeman (Ref #1) (psig) Prioleau (Ref #2) (psig) *psig is pounds per square inch gauge pressure Environmental data that Exponent (the scientific investigation team) collected and evaluated are listed below. All of these values were obtained via weather reports or direct measurements by the team. a. The likely temperature of the room when the pressures of the footballs were measured prior to the game (67 71 F). b. The likely temperatures on the field during the first half (48 50 F). 3

4 c. The likely temperature of the room when the pressures of the footballs were measured at halftime (71 74 F). d. The time that elapsed from when the balls were brought into the Official s locker room at half-time and all the measurements were made, 13.5 minutes. e. Some balls were damp; others were dry. f. Atmospheric pressure of the day was approximately 1 atm (estimated) g. Volume of a football for the pressure range of 10.5 to 13.5 psig is constant at 4.24 L. (Tested by scientific team.) All of these values were obtained via weather reports or measurements made by the investigative team. Although all the factors contributed to variations in football pressures, the main detail affecting the pressure change was the time at which football pressures were checked upon bringing the balls from the field to the locker room at half time. Additional Information that Students Need a. The students can use either the Ideal Gas Law (PV = nrt) or Amonton s law (also called Gay-Lussac s Law) (P 1 T 1 = P 2 T 2 ), which assumes no air was let out of ball (i.e. moles of gas and ball volume remain constant). b. Students will need to know the difference between gauge pressure and absolute pressure. Gauge pressure is the pressure measured using a pressure gauge; it is the difference between atmospheric pressure and the pressure inside the object, the ball in this case. Absolute pressure is the true pressure in the object, calculated as the sum of the atmospheric pressure and the pressure of gas in the object. To use the ideal gas law (or any variation of it), you must use absolute pressure. To convert from psig to psi simply add 14.7 psi. c. When using the ideal gas law, the units you choose affect the gas constant, R. In order to use R= atm-l/mol-k, your pressure must be in atmospheres, volume in liters, amount of gas in moles and temperature in Kelvin. d. Two important unit conversions needed are: Kelvin temperature = ( F-32)5/ K 1 atm = 14.7 psi. 4

5 Sample Calculations (from three different evidence collection perspectives) Method 1: Using Amonton s Law (aka: Gay-Lussac s Law) Parameters for the Best Case Scenario for the Variable Value Patriots (highest initial and lowest final temperatures) Initial pressure of Patriot s ball 12.5 psi Initial absolute pressure of Patriot s ball P = 27.2 psi Highest possible temperature when balls were filled T 1 71⁰ F (294.8 K) Football s lowest possible absolute pressure at half-time P 2? Lowest possible temperature of ball (on field at halftime T 2 48⁰ F (282.0 K) P 1 /T 1 = P 2 /T psi/294.8 K = P 2 /282.0 P 2 = 26.0 psi (absolute pressure) = 11.3 psig Under the best case scenario for the Patriots, the lowest possible pressure that the Patriot s footballs should have been was 11.3 psig. This means that at least 3 of the 11 Patriot s balls were under-inflated according to Prioleau s gauge and 8 of the 11 Patriot s balls were under-inflated according to Blakeman s gauge. For argument s sake, I ve performed the same calculations for the Colt s balls although these balls truly serve as a control group since no allegations have been made about these balls. Parameters for the Best Case Scenario for the Variable Value Colts (highest initial and lowest final temperatures) Initial pressure of Colt s ball 13.0 psi Initial absolute aressure of Patriot s ball P = 27.7 psi Highest possible temperature when balls were filled T 1 71⁰ F (294.8 K) Football s lowest possible absolute pressure at halftime P 2? Lowest possible temperature of ball (on field at halftime) T 2 48⁰ F (282.0 K) P 1 /T 1 = P 2 /T psi/294.8 K = P 2 /282.0 P 2 = 26.5 psi (absolute pressure) = 11.8 psig Under the best case scenario for the Colts, the lowest possible pressure that the Colt s footballs should have been is 11.8 psig. All of the Colts footballs were above this pressure. 5

6 Method 2: Using Average Pressure Differences Data from Wells Report Pressure values in psig Initial pressure of Patriot s ball 12.5 Patriot average football pressure at half-time or11.49 Average pressure drop in Patriot balls 1.39 or 1.01 % pressure drop 10.4% or 8.1% Initial pressure of Colt s ball 13.0 Colt average football pressure at half-time or12.44 Average pressure drop in Colt balls 0.37 or 0.56 % pressure drop 2.8% or 4.3% Basic Assumptions: 1) All data collected is correct. 2) Volume of football remains constant at the temperature and pressure range studied. 3) The moles of gas within the footballs for both teams remained unchanged. Since the footballs of both teams experienced the same environmental conditions, it is expected that the balls would have the same percent pressure drop, but the Patriot drop is much greater than the Colt drop. For example, A hypothetical gas 1 has the following parameters: P 1 = 10.0 atm T 1 = K P 2 =? atm T 2 = 282 K P 1 /T 1 = P 2 /T atm /294.8 K = P 2 /282.0 P 2 = 9.57 atm ( )/10 * 100 = 4.3% drop A hypothetical gas 2 has the following parameters: P 1 /T 1 = P 2 /T 2 P 1 = 15.0 atm T 1 = K 15.0 atm /294.8 K = P 2 /282.0 P 2 =? atm T 2 = 282 K P 2 = 14.3 atm ( )/15 * 100 = 4.3% drop 6

7 Method 3: Moles of Gas on Balls (PV=nRT) Parameters for the Best Case Scenario for the Variable Value Patriots (highest initial and lowest final temperatures) Initial pressure of Patriot s ball 12.5 psig Initial absolute pressure of Patriot s ball P = Unit conversion 1.85 atm 27.2 psi Highest possible temperature when balls were filled T 1 71⁰ F K Volume of football V L 4.24 L Moles of gas in ball before game n 1? Football s average pressure at half-time P or psig Initial absolute pressure of Patriot s ball P or 26.2 psi 1.76 or 1.78 atm Lowest possible temperature of ball (on field at halftime) T 2 48⁰ F K Moles of gas in ball at half-time game n 2? PATRIOTS: Before game: moles of gas in football = (1.85 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(295 K) After game (gauge 1): moles of gas in football = (1.76 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(282 K) After game (gauge 2): moles of gas in football = (1.78 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(282 K) Under the best case scenario for the Patriots, the average moles of gas in their footballs at halftime were the same as before at moles. The same calculations were performed for the Colt s balls (although these balls truly serve as a control group since no allegations have been made about these balls). Parameters for the Best Case Scenario for the Variable Value Colts (highest initial and lowest final temperatures) Initial pressure of Colt s ball 13.0 psig Initial absolute pressure of Patriot s ball P = 1.89 atm 27.7 psi Highest possible temperature when balls were filled T 1 71⁰ F K Volume of football V L 4.24 L Moles of gas in ball before game n 1? 7

8 Football s average pressure at half-time P or psig Initial absolute pressure of Patriot s ball P or 27.1 psi 1.86 or 1.85 atm Lowest possible temperature of ball (on field at T 2 48⁰ F K half-time) Mo Moles of gas in ball at half-time game n 2? COLTS: Before game: moles of gas in football = (1.89 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(295 K) After game (gauge 1): moles of gas in football = (1.85 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(282 K) After game (gauge 2): moles of gas in football = (1.86 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(282 K) Under the best case scenario for the Colts, the average moles of gas in their footballs at half-time were which is more than the initial moles of gas (0.331 mol). This leads us to believe that the reported temperatures and/or pressures values are not accurate. 8

9 Claims, Evidence, Reasoning Style Written Explanation How to write the Claim? The Claim should be one or two concluding statements that answer the original question, Could the lower pressure of the Patriot s footballs be a result of the environmental conditions during the game? It should be clear, specific and answer the question. How to write the Evidence portion? The Evidence portion of paper should tell the reader what you determined. This section should begin with text stating your major results/findings, referring to appropriate data table(s). It should progress in a logical sequence that guides the reader through the evidence that answers the original question. It will include a properly-made table(s) with all data used and any calculated values. The evidence must be sufficient and relevant; not all available data is relevant. (Interpretations of the evidence should be included in Reasoning portion of paper.) How to write the Reasoning portion? The Reasoning portion links the background information (gas laws, knowledge of game of football, NFL protocol, and data collected by Investigative team) that justifies your claim to the evidence and your interpretation of the new findings. It should be written in a clear, concise manner in first person. If more than one analysis was performed, then address them in the same order as in the evidence portion. If the findings are not conclusive, then recommend a follow up investigation if possible. (Modified from McNeil and Krajcik 7 and 8 9

10 Sample Claim, Evidence and Reasoning Explanations CER #1 Claim: The lower pressures of the Patriot s footballs could not have been a result solely of the environmental conditions of the day. Evidence: I assumed that the number of moles of gases in the football remained unchanged (no tampering with the balls) and since we were dealing with minimal pressure changes that the volume of the ball remained constant. I then needed to determine what conditions would result in the largest pressure change. Reasoning: According to the Kinetic Molecular theory, when a confined gas s temperature decreases, the particles have less KE causing the particles to hit the sides of the container less often and with less force. This behavior results in a lowering of the pressure in the container and can be calculated using Amonton s law (also called Gay-Lussac s Law), P 1 /T 1 = P 2 /T 2 (where the volume and moles of the gas remain unchanged). Evidence: To calculate the largest possible pressure change, I assumed the balls were filled at the highest possible temperature (71⁰F or K) and were measured at half-time at the lowest possible temperature (48⁰F or K). The initial pressure of the Patriot s balls was 12.5 psig (or 27.2 psi). After plugging these values into Amonton s law, it was found that the lowest possible pressure for any of the Patriot s ball was 26.0 psi (or 11.3 psig) P 1 /T 1 = P 2 /T psi/294.8 =P 2 /282.0 P 2 = 26.0 psi (or 11.3 psig) Lowest possible pressure for the environmental conditions The same calculation was done for the Colt s balls, except their initial pressure was 13.0 psig (27.7 psi). P 1 /T 1 = P 2 /T psi/294.8 =P 2 /282.0 P 2 = 26.5 psi (or 11.8 psig) Lowest possible pressure for the environmental conditions So the lowest possible pressure for the Colt s balls should have been 11.8 psig. All four of their balls were well above this value. Reasoning: Therefore, since several of the Patriot s balls were below the expected lowest pressure, it is reasonable to conclude that the environmental conditions alone could not have caused the excessively low pressures. 10

11 CER #2 Claim: The lower pressures of the Patriot s footballs could not have been a result solely of the environmental conditions of the day. Evidence: I assumed that the number of moles of gases in the football remained unchanged (no tampering with the balls) and since we were dealing with minimal pressure changes that the volume of the ball remained constant. Reasoning: According to the Kinetic Molecular theory, when a confined gas s temperature decreases, the particles have less KE causing the particles to hit the sides of the container less often and with less force. This behavior results in a lowering of the pressure in the container. So we expect that there will be a decrease in the pressure for both teams balls, but the % drop in pressure should be the same for the two teams. Evidence: The average pressure at half-time of the Patriot s footballs was psig or psig depending on the gauge. The average pressure at half-time of the Colt s footballs was psig or psig depending on the gauge. The Patriot s starting pressure was 12.5 psig, so the average pressure drop was 1.39 psig or 1.01 psig leading to a drop of 10.4 or 8.1%. The Colt s starting pressure was 13.0 psig, so the average pressure drop was 0.38 psig or 0.56 psig leading to a drop of 2.8 or 4.3%. Reasoning: It is assumed that the balls of each team experienced the same environmental conditions and therefore, should have about the same % drop in pressure. But the Patriot s % drop was much greater than the Colt s. As of result, the lower pressures of the Patriot s footballs could not have been a result solely of the environmental conditions of the day. 11

12 CER #3 Claim: The data are insufficient to determine if the lower pressures of the Patriot s footballs were a result of the environmental conditions of the day. Evidence: I assumed that both teams footballs experienced the same conditions on game day and that the volume of a football was constant for the range of pressures and temperatures of the day. I used the maximum temperature of locker rooms during the inflation process and the minimum field temperature to simulate the conditions that would bring about the largest change in pressure. The moles of gas inside the footballs were then calculated using PV=nRT for the conditions before the game and at half-time for both teams. For all calculations I used a ball volume of 4.24 L. The initial pressure for the Patriot s balls was 12.5 psig (1.85 atm) and for Colt s balls was 13.0 psig (1.89 atm). The temperature during inflation for both teams was 71⁰ F (295 K) and the temperature at half-time was 48⁰ F (282 K). Patriot- before game: moles of gas in football = (1.85 atm)(4.24 L) (.0821 atm-l/mol-k)(295 K) = mol Patriot- after game (gauge 1): moles of gas in football = (1.76 atm)(4.24 L) (.0821 atm-l/mol-k)(282 K) Patriot- after game (gauge 2): moles of gas in football = (1.78 atm)(4.24 L) (.0821 atm-l/mol-k)(282 K) = mol = mol Colts- before game: moles of gas in football = (1.89 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(295 K) Colts- after game (gauge 1): moles of gas in football = (1.85 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(282 K) Colts-after game (gauge 2): moles of gas in football = (1.86 atm)(4.24 L) = mol (.0821 atm-l/mol-k)(282 K) Reasoning: If no gas is added or removed from the balls, then the number of moles of gas must remain the same regardless of the conditions. According to the Kinetic Molecular theory, when a confined gas s temperature decreases, the particles have less KE causing the particles to hit the sides of the container less often and with less force. This behavior results in a lowering of the pressure in the container, but has no effect on the number of moles of the gas present. So we 12

13 expect that there will be a decrease in the pressure, but not an increase or decrease in the moles of gas. Under the best case scenario for the Patriots, the average moles of gas in their footballs after the game were the same as before at moles. Under the best case scenario for the Colts, the average moles of gas in their footballs after the game were which was more than their initial number of moles. Since it is not believed that the Colts tampered with their balls, then we (the student investigative team) presumed values for the temperatures and/or pressures must not be completely accurate; therefore, we cannot draw any conclusions about the cause of the pressure differences. 13

14 Final Ruling on the Controversy The investigative team concluded that there was no reason why any of the footballs should have been under-inflated. So why did some of the Patriot s balls have lower than expected pressures if not attributable to environmental or physical factors? This is where the investigators turned to evidence of foul play based on text messages and extensive interviews with the people involved (pgs of Wells Report 3 ). Such evidence is outside the science goals of this exercise, but can add context and intrigue to the conversation that accompanies the exercise. The teacher should avoid choosing sides on the matter. When the Well s Report 3 was released in May, 2015, the NFL announced that it was more probable than not that Patriots personnel deliberately violated the rules and that Tom Brady, the Patriot quarterback, was knowledgeable of the deflating. The NFL penalized the Patriot s organization $1 million dollars and suspend Tom Brady for four games at the start of the 2015 season 9. Brady appealed the suspension and the case went to court. 10 On September 3 rd, 2015 US District Court Judge Richard Berman nullified the suspension on several points (listed below) and Brady was allowed to start the season. 11 Brady did not receive the proper advance notice that he was going to be disciplined or of the severity of the penalties he could receive. Brady was denied the right to cross-examine NFL general council Jeff Pash who reviewed the Wells Report and provided comments and edits. Punishments were not consistent across the league comparing it to a ball-warming issue by the Carolina Panthers where they only received a warning. (FYI: The NFL contended that the Panthers were not hiding the fact that they were warming the balls.) 14

15 Follow-up Activities: A. Review of the Engineering Designs used to test the footballs (Information in Exponent Report) The Investigative team employed some innovative and high-tech ways of testing various physical factors to evaluate their effect on a football s pressure. (See below.) - Game Use 1000 Load cycles of 650 lbs/sec page 32 - Natural Leak Rate Standard Permeability Methods (ASTM D (2009) e1) not discussed in report page 33 -Vigorous Rubbing Infrared Camera page 33 -Multiple Gauging-- Needle insertion test page 35 -Humidity of Air Used to Fill the Football Humidity Chambers page 36 - Football Volume Changes High Resolution Laser scan page 37 - Gauge Function Test Gauge Manifold page Gauge to gauge variability Gauge Accuracy Temperature Effects on Accuracy Battery Level Impact on accuracy Long Term Repeatability Activity: Assign different groups a physical factor analysis to review (game use, leak rate, etc) from the report. Then make a poster (or another method to present) that includes the following: What was being analyzed? Methods used (including specialized equipment) Results Final Conclusion regarding its effect on the football pressure. B. Data Collection Issues In small groups have students read pages 5-12 of Exponent s Report (Appendix A of Well s Report) being sure to look closely at the tables. Then answer the following question. 1. What concerns did the investigators have with the data given to them? (The gauges used to measure the pressure of the footballs didn t read the same. One gauge seems to consistently read higher than the other for the Patriot s balls. But when the Colt s balls were measured, the gauges appear to have been switched. In addition, some of the data appears to have been recorded incorrectly.) 2. How did the investigators tried to rectify their concerns? 15

16 (The investigators analyzed the data in multiple ways making various assumptions to see how it affected the overall question.) 3. Did their concerns affect the overall investigation? (In the end the investigators determined that regardless of any recording errors or gauge switching, the Patriot s balls had a significantly larger pressure drop than the Colt s balls.) 4. If there is a next time, what should be done differently to insure the accuracy of the data? (Answers will vary.) C. Social Media vs Independent Expert Investigation Divide the class into groups each assigned with one of the tasks listed below. After students have researched and read, begin a discussion of the initial reports on Deflategate (pre-wells Report), the Wells and Exponents reports, and then the response to the Wells Report. This exercise allows students to explore social media and how sometimes news is really hearsay and speculation. It also introduces students to the world of politics in sports and the need for independent, expert investigations. Tasks: Find and read at least 3 articles on Deflategate dated BEFORE the Wells Report was published in May, Read the Executive Summary of Wells Report (This is very long, so two groups should be assigned different parts of the report.) Read the Executive Summary from Exponent (Appendix of Wells Report) (This is very long, so again two groups should be assigned different parts of the report.) Find and read at least 3 articles on Deflategate dated AFTER the Wells Report was published in May,

17 References 1. Encyclopedia Britannica. National Football League. Football-League (accessed Oct 2015). 2. Constitution and By Laws of the National Football League. (accessed Oct 2015). 3. Wells, T. V.; Karp, B. S.; Reisner, L. L. Investigative Report Concerning Footballs Used During the AFC Championship Game on January 18, (accessed Oct 2015). 4. Patriots Deflation Controversy. (accessed Oct 2015). 5. Burnett, A. J. Deflate-Gate: Could Weather Have Played a Role in Deflated Balls? 6. Eager, E.; Eberle, M.; Peirce, J. How Infectious Was #Deflategate? (assessed Oct 2015). 7. McNeill, K. L.; Krajcik, J. Assessing Middle School Students Content Knowledge and Scientific Reasoning through Written Explanations. Handout-with-examples.pdf (accessed Oct 2015). 8. The Structure, Format, Content, and Style of a Journal-Style Scientific Paper: Discussion. Department of Biology, Bates College. (accessed Oct 2015). 9. NFL Press Release. NFL Statement on Discipline Imposed on New England Patriots for Violating NFL Policy on Integrity of Game. (accessed Oct 2015). 10. ESPN News Service. Sources: NFL, NFLPA Engaged in Tom Brady Settlement Talks. (accessed Oct 2015). 11, Around the NFL. Judge nullifies Tom Brady s Four-game Suspension. fourgamesuspension (accessed Nov 2015) 17