Citizen Science # 18 by Jamie Zvirzdin

Energy Demystified: Let’s Get Chemical

If you’ve joined us this year in unlocking the secrets of energy (all past columns of “Citizen Science” are available online, by the way, at allotsego.com), you’ll be pleased to hear that my mile run time—thanks to kinetic energy, my frenetic dog and her elastic running leash—is down from 12 minutes 31 seconds to 11 minutes 43 seconds.

Why should you care? You shouldn’t, really, but I am determined to win a bet I made with my friend to run three times a week for a whole year. I’m not a natural runner, but with some knowledge about chemical potential energy (chemical PE), I think I can game the system and win the bet.

Chemical potential energy is like a coiled spring (remember elastic potential energy?), a spring hidden in molecular bonds. Breaking these bonds, like when we burn fuel or calories, releases energy; forming new bonds stores energy. Strong bonds, like carbon-carbon triple bonds (C≡C), hold more energy than weaker ones, like carbon-carbon single bonds (C–C). If more energy is released than absorbed, we get heat and light, like fireworks; if more energy is absorbed, like leaves drinking in the sun during plant photosynthesis or me eating too much at a picnic, the energy is stored for later use.

Actually, a Fourth of July picnic in the park with family, friends and neighbors presents the perfect scenario to think about all the ways we use chemical potential energy without even thinking about it. On a deeper level, the bonds we chemically make or break—and maybe make again—are reflected in the bonds we create or destroy with other people, locally and nationally. I’m neither a politician nor a chemist, but I can at least energetically list and vividly describe what is happening with the chemical bonds in action and reaction at our celebratory picnic:

Potato Salad! (And potato chips!) The complex carbohydrates (starch) in potatoes store chemical PE. Our bodies digest this starch through enzymatic hydrolysis, which is a fancy way to say we chemically convert lovely, delicious carbs into glucose, which in turn creates the almighty adenosine triphosphate (ATP) that you don’t really remember from Mr. Smith’s 9th-grade biology class. ATP, in turn, gives us energy not only for the cellular upkeep of the body but also to run around with a squirt gun and make your little sister hopping mad.

Watermelon! This juicy summer favorite bursts with natural sugars—primarily fructose—which likewise store chemical PE. When you bite into a slice of watermelon, the juice drips all down your chin and your shirt, but you hardly notice because you’re already soaked from your sister’s water-balloon revenge. As you chew, your digestive system breaks down the fructose through that same process of enzymatic hydrolysis. You’re ready for round two of sibling rivalry as the parents fire up the grill with…

Charcoal or propane! The fuel we use in grilling can store chemical PE in carbon or hydrocarbon bonds (that is, carbon atoms are connected either to other carbon atoms or to hydrogen atoms). When we ignite the charcoal or propane, we cause a combustion reaction with oxygen, which again releases heat energy. This exothermic (“heat-releasing”) reaction converts the stored chemical energy into thermal energy, which helps us cook our…

Corn on the Cob! Corn kernels, like potatoes, also contain carbohydrates in the form of starch. Boiling or grilling corn involves gelatinization, where the starch absorbs water and swells, making the corn tastier and easier to digest. This process is endothermic (“heat-absorbing”), which means it takes in heat from the surroundings. Like a leaf absorbing sunlight to make food in photosynthesis or like ice melting by absorbing heat, the corn requires heat energy to help water break into the starch.

Grilled Hamburgers and Hot Dogs! Both kinds of meat…as well as surprisingly delicious plant-based alternatives…contain proteins and fats that store chemical PE. Cooking these foods relies on the Maillard reaction, where proteins and sugars react under the heat energy to brown the meat and change its flavor. Grilling also triggers pyrolysis, a process that breaks down complex molecules and releases more heat. We digest the proteins and fats through more enzymatic reactions, converting them once again through chemical PE into usable energy in our bodies.

Your mother, tired of her squabbling, soaked, ketchup-stained children, tries a new tactic as the sun goes down and stomachs settle…

Sparklers! Sparklers are coated with a mix of fuel (like charcoal or sulfur), oxidizers (such as potassium nitrate), and metal powders. When your dad lets you light a sparkler with a match, a combustion reaction unleashes heat and light energy . . . yet another example of chemical PE in action. The metal powders produce the bright sparks as they oxidize (as they react with oxygen). Once the whole alphabet has been drawn in the air and all the spent sparklers are safely in the bucket of water, it’s time for…

Apple Pie and Ice Cream! The carbohydrates in the crust and the sugars in the apple filling store chemical PE. Baking induces caramelization (the breakdown of sugar) and Maillard reactions (the lovely browning of the crust), releasing a little heat energy but mostly enhancing flavor and color. After you eat the ice cream, digestive enzymes break down the sugars into glucose and the fats into fatty acids and glycerol.

Alcohol! Alcoholic drinks like beer and wine contain ethanol, which stores chemical PE. When the grownups break out the alcohol, their bodies metabolize the ethanol through oxidation reactions in the liver, primarily involving the something called enzyme alcohol dehydrogenase, a protein that triggers your liver to break down the alcohol into acetaldehyde, a toxic organic compound you might regret the next day and down the road. Alcohol also contains quite a bit of sugar, which, like the sugar previously consumed, releases energy in the form of heat and provides ATP for cellular activities.

At this point in the evening, almost everyone is thoroughly saturated with way more sugar and carbs than a body usually needs. Our amazing bodies, which evolved to store extra energy away for hard times, start to convert the extra glucose into fat through a process called lipogenesis. We absolutely need fat to store chemical PE, insulate and protect organs, and help us absorb essential vitamins, but only 20–35 percent of our total daily calories should come from healthy fats. However, the occasional indulgence is OK, if paired with mindful eating, reducing food waste, and following a “healthy planetary diet,” as suggested by the Harvard T.H. Chan School of Medicine. I believe it’s fully possible to still have fun and strengthen important societal bonds in a way that keeps our bodies (and our planet) healthy.

It’s now time to settle into the lawn chairs or flop down on blankets to listen to the local radio with the help of…

Radio Batteries! The chemical potential energy in the batteries powers the old-school radio someone brought, although the batteries inside our smart phones and speakers function similarly. Inside the batteries, chemical reactions between the anode (negative electrode) and the cathode (positive electrode) take place through the electrolyte (the medium that allows ion movement within the battery), and those reactions, in turn, produce electrical energy and sound energy. We can now sit and sing along as the songs sync up with the…

Fireworks! Fireworks contain chemical PE stored in oxidizers, fuel, and color-producing compounds (from the USGS.gov website: “Barium produces bright greens; strontium yields deep reds; copper produces blues; and sodium yields yellow”). When ignited, the combustion transforms our powerful chemical PE into heat, sound and light. The heat-releasing (exothermic, remember?) reaction of aluminum powder is the cause of the reverberating booms in the sky that you nevertheless feel deep in your chest.

How can this imagined patriotic party help me win my running bet? Besides modulating my Fourth of July festivities to avoid the absurd amounts of excess glucose I’ve consumed in the past, I’m also going to make chemical potential energy work for me in the form of something called “running gels.” They’re not very tasty, but they provide easy-to-break glucose, amino acids and caffeine for those of us crazy to make dumb bets for entire years. One running gel gives me the quick energy boost and focus I seem to need, at least right now, to get off the couch, into my running shoes, and out the door with my dog.

Life is defined by the bonds we make and the bonds we break, on many levels. This Fourth of July, remember that strong bonds hold more energy than weaker ones, but even weak bonds can help us lead better, happier, healthier lives. Happy July to you!

Jamie Zvirzdin researches cosmic rays with the Telescope Array Project, teaches science writing at Johns Hopkins University and is the author of “Subatomic Writing.”