version submitted to Am J Phys

food_energy.tex

@@ -34,9 +34,9 @@
 
 % AJP header
 %When submitting the manuscript for review, do not include the author's name or institution
-\author{Nathan T. Moore}
-\email{nmoore@winona.edu}
-\affiliation{Physics, Winona State University, Winona, MN 55987}
+%\author{Nathan T. Moore}
+%\email{nmoore@winona.edu}
+%\affiliation{Physics, Winona State University, Winona, MN 55987}
 
 %IOP header
 %%\title[How many acres of potatoes does a society need?]{How many acres of potatoes does a society need?}
@@ -57,7 +57,10 @@ Science and Social Policy classes are full of bespoke units and involve many dif
 \section{Introduction}
 When the United States entered World War One one of the problems they faced was logistics.  How much food do you need to ship overseas to Europe to feed a million soldiers?  That early work in nutrition led to the $3000$ Calorie diet many people remember from secondary Health Education class.  A bit about ``Calorie'' (uppercase) vs ``calorie'' (lowercase) units you might remember: $1~Calorie = 1~kilocalorie~(kcal)$, and a dietitian might build a $3000 kcal$ diet for a 20 year old basketball player.  A \textit{calorie} is the amount of energy it takes  to heat a gram of water by a degree Celsius.  There are about $4.2$ Joules in a single calorie, and a Joule occurs all over introductory  physics.  If you need to buy a new home furnace, the sales brochure might advertise that it is capable of delivering $100,000$ BTU's of heat each hour.  What's a BTU? Heat a pound of water by $1^{\circ}F$.  Of course Heat Pumps are far more efficient than simply burning methane or propane, but they consume kilo-watt-hours (kWh) of electricity, not BTU's.  What's a kWh?  Run a $1000$ Watt toaster for an hour and you'll have pulled one kWh off the grid, it will cost you about $\$0.13$ in Minnesota.  If you decide to put solar panels in your backyard, they will probably collect about $10\%$ of the $3.5kWh$ the  the sun delivers to each square meter of your lawn (in Minnesota) each day.  
 
-As the previous paragraph illustrates, there are a frustratingly large number of different units in an ``Energy'' class.  At Winona State, this 3 credit class fulfills a ``Science and Social Policy'' general education requirement and is taken by students from across the university.   Lots of college majors don't require a math class beyond algebra or introductory statistics and the population is largely math-averse. You could jokingly say that one of the main things students learn in the class is unit conversion, but it isn't far off.  Nearly every field finds energy a useful representation, and every profession has their own set of units and terminology most well suited for quick calculation.  Would a medical lab scientist talk about the fractional acre-foot of urine needed test kidney function?  No, but someone in the central valley of California would certainly care about the acre-feet of water necessary to grow almonds!  Does a gas station price their gasoline in dollars per kWh? Given the growing electrification of cars, they might soon.
+As the previous paragraph illustrates, there are a frustratingly large number of different units in an ``Energy'' class.  At 
+XXXXXX
+%Winona 
+State, this 3 credit class fulfills a ``Science and Social Policy'' general education requirement and is taken by students from across the university.   Lots of college majors don't require a math class beyond algebra or introductory statistics and the population is largely math-averse. You could jokingly say that one of the main things students learn in the class is unit conversion, but it isn't far off.  Nearly every field finds energy a useful representation, and every profession has their own set of units and terminology most well suited for quick calculation.  Would a medical lab scientist talk about the fractional acre-foot of urine needed test kidney function?  No, but someone in the central valley of California would certainly care about the acre-feet of water necessary to grow almonds!  Does a gas station price their gasoline in dollars per kWh? Given the growing electrification of cars, they might soon.
 
 Everyone eats, maybe not $3000 kcals$ per day, but at least something every day.  When I teach our energy class,\cite{Energy_textbook,PFFP} 
 I spend a few weeks talking about food energy before all other types.  While food production is not central to climate change and wars over oil, food is essential in a way that diesel and gasoline are not.  Vehicle fuel makes modern life possible, but we could live, unpleasantly, without it.  We can't live without fats and protein.  
@@ -70,7 +73,10 @@ To introduce Food Energy, I ask the students to work through a few questions:
 \centering
 \includegraphics[width=\columnwidth]{at_the_buffet.jpg}
 \caption{
-A proto-college-student at Winona's China King Buffet, dreaming about visiting the steam tables every day. 
+A proto-college-student at 
+XXXXX's
+%Winona's 
+China King Buffet, dreaming about visiting the steam tables every day. 
 }
 \label{buffet}
 \end{figure}
@@ -105,7 +111,10 @@ $+3000\frac{kcal}{hour}\approx +3500W$.
 In medicine, these slopes are effectively equivalent to ``Metabolic Equivalent of Task'' (METS), a common measure in cardiology and exercise physiology.  METS is power normalized by mass, $1METS=1\frac{kcal}{kg\cdot hour}$, and METS levels are available for many different physical activities.\cite{METS}
 
 \subsection{Burning off food energy}
-Imagine that after eating a $600kcal$ bacon-maple long-john (donut), you decide to go for a hike to ``work off'' the Calories.  Winona State  is in a river valley bounded by $200m$ tall bluffs.  How high up the bluff would you have to hike to burn off the donut?  
+Imagine that after eating a $600kcal$ bacon-maple long-john (donut), you decide to go for a hike to ``work off'' the Calories.  
+XXXXXX
+%Winona 
+State  is in a river valley bounded by $200m$ tall bluffs.  How high up the bluff would you have to hike to burn off the donut?  
 Useful information: human muscle is about $1/3$ efficient, and on Earth's surface, gravitational energy has a slope of about $10~\frac{Joules}{kg\cdot m}$.
 
 \begin{figure}[h]