Chemistry for Breakfast

The Amazing Science of Everyday Life

Mai Thi Nguyen-Kim, claire Lenkova

• Publisher: Greystone Books
• Year: 2021
• ISBN:
  9781771647496
• Topic: Ciencias físicas
• Subtopic: Química

FINALIST for the Subaru Prize for Excellence in Science Books

"This book shows that chemistry is not just relevant to life; it's really, really interesting."— Foreword Reviews, STARRED review

A perfect book for readers of The Physics of Everyday Things and Storm in a Teacup

Have you ever wondered why your alarm clock sends you spiraling? Or how toothpaste works on your teeth? Why do cakes and cookies sometimes turn out dry? (Hint: you may not be adding enough sugar.) In Chemistry for Breakfast, award-winning chemist and science communicator Mai Thi Nguyen-Kim reveals the amazing chemistry behind everyday things (like baking and toothpaste) and not-so-everyday things (like space travel). With a relatable, funny, and conversational style, she explains essential chemical processes everyone should know—and turns the ordinary into extraordinary.

Over the course of a single day, Mai shows us that chemistry is everywhere: we just have to look for it. In the morning, her partner's much-too-loud alarm prompts a deep dive into biological clocks, fight-or-flight responses, and melatonin's role in making us sleepy. Before heading to the lab, she explains how the stress hormone cortisol helps wake us up, and brews her morning coffee with a side of heat conduction and states of matter.

Mai continues her day with explainers of cell phone technology, food preservation, body odor, baking, the effects of alcohol, and the chemistry behind the expression "love drunk." All the while, she shows us what it's really like to be a working chemist, and fights against the stereotype of a nerd playing with test tubes in a lab coat.

Filled with charming illustrations, laughter, and plenty of surprises, Chemistry for Breakfast is a perfect book for anyone who wants to deepen their understanding of chemistry without having prior knowledge of the science. With Mai as your guide, you'll find something fascinating everywhere around you.

1 Obsessed with Chemistry

BRRING-BRRING-BRRING!!!

I almost fall out of bed in fright. My heart is racing.

Furious, I want to scream “Matthiiiiiiiaaaaaaaaaaas,” but my linguistic faculties don’t quite seem to be working yet. My body’s in a strange sort of limbo, halfway between dozing and hand-to-hand combat. I throw myself at Matthias/his cell phone and flail around until I manage to turn off his awful alarm. It’s six in the morning, dammit!

Matthias has a terrible habit of getting up in the middle of the night to go running, at least twice a week—well, I consider 6 a.m. to be the middle of the night. Unfortunately, this always means that I need to wake up slightly before him so that my day doesn’t start with an influx of stress hormones.

I prefer to be woken by a barely audible tinkling, as if by a fairy—otherwise I start my day with palpitations—but Matthias needs at least 100 decibels and this awful BRRING-BRRING-BRRING to wake up at all. So I usually set my alarm for one minute before his to mentally prepare myself for the stress. Last night when I set my alarm, however, I didn’t know he was planning to exercise so early this morning.

I open the drapes to reduce Matthias’s melatonin level.

“Matthias,” I eventually manage to say.

“Hmm,” he mumbles, still half asleep. Unbelievable.

THE MOLECULE MELATONIN is also popularly known as the “sleep hormone.” It’s produced in the pineal gland, a small gland in the middle of the brain. There’s a very good reason for its nickname; melatonin plays an important role in our circadian rhythm (from the Latin circa dies, “around the day”), our internal sleep-wake cycle. The higher our melatonin level, the more tired we feel. Conveniently, light helps to reduce melatonin concentration, and it finally seems to be having an effect on Matthias.

I feel compelled to see the world in molecules, but it’s a nice feeling. Basically, I’m obsessed with chemistry. It makes me sad to think about all the nonchemists going about their lives, not thinking about molecules at all. They don’t even know what they’re missing. Ultimately, anything that interests you as an individual can somehow be explained through chemistry. And you, dear reader, are in fact nothing more than a mound of molecules reading about molecules. And chemists are mounds of molecules thinking about molecules. It’s almost spiritual.

So what does my morning look like in molecules?

How well we wake up in the morning is largely determined by two molecules. We need less of one—melatonin—and more of the other, the stress hormone cortisol, which is automatically released in the morning. “Stress hormone” might not sound great, but a moderate amount of cortisol simply helps us to get going. Normally, this wonderful service provided by our body doesn’t even need an alarm clock. The BRRING-BRRING-BRRING may have been a bit too much and has triggered an actual fight-or-flight response in my body, an ingenious emergency system tried and tested since primeval times to save us from mortal danger.

Like pain, stress is generally a welcome bodily response. Pain tells us that something isn’t right, and stress helps to save our lives. Imagine that you’re walking around in the Stone Age and a saber-tooth tiger crosses your path (“saber-tooth cat” would be more accurate, but “tiger” is more dramatic so let’s stick with that). If your body didn’t immediately release a flood of stress hormones, you’d stand there looking stupid rather than reacting quickly—grabbing your spear (fight) or climbing the nearest tree (flight)!

We must assume that the saber-tooth tiger also experiences a fight-or-flight response. It has never been established whether humans really were a meal of choice for saber-tooth tigers. After all, humans were “predators” too, and an encounter like this may have been a meeting of two hunters who respected one another. In any case, the fight-or-flight response is older than the human race, an alarm system installed in many creatures. And how does this alarm system work? Through molecules, of course.

The molecules lying dormant in our bodies first need to be roused by some sort of trigger. In the Stone Age, this might have been a saber-tooth tiger; today, it’s Matthias’s monster alarm clock. The clock’s acoustic signal sends a nerve impulse from the brain to the adrenal glands via the spinal cord. Along with the pineal gland, the adrenal glands are among our bodies’ most important hormone factories. This nerve impulse causes the adrenal glands to release what is probably the best-known stress hormone—adrenaline, which is promptly pumped into the bloodstream and makes its way to various organs. A hormone is nothing more than a messenger substance, a molecule that carries important information. And in this case, the message is PANIC!!

While adrenaline is rushing through the bloodstream—and disappearing just as quickly—another hormone is gearing up for the stress war. ACTH (adrenocorticotropic hormone) is produced in the pituitary gland and travels through the bloodstream to the adrenal glands, the base camp for the fight-or-flight battle.

As soon as it arrives, ACTH unleashes a whole chain of chemical reactions. I like to picture it like an epic movie battle scene. Adrenaline is the forerunner who raises the alarm, while ACTH is the army commander who raises their fist and lets out the first battle cry, mobilizing the army and setting the carnage in motion. Finally, cortisol enters the bloodstream and makes its way to various organs as well.

Hormones can trigger a variety of physical reactions. Symptoms of a fight-or-flight response include an accelerated pulse, greater blood circulation in the muscles (RUN!!!), reduced blood circulation in the digestive system (drop everything, we have more important things to do!), deeper breathing, dilated pupils, sweating, goose bumps, and heightened awareness.

All these physical reactions to the release of my stress hormones mean that I am now, of course, wide awake, but the feeling of mortal danger isn’t exactly pleasant. I can’t blame this on molecules. Our bodily chemistry is designed for survival. The poor stress molecules don’t know that Matthias’s alarm isn’t threatening my life. They just want to help.

The problem is that our modern world is full of stress—at school, at work, in our relationships. But very few situations are actually life-threatening, at least not acutely. Chronic stress definitely has an effect on our health. Luckily, to ensure that we and our molecules don’t crack up completely, our stress system has a negative feedback loop that makes sure the body doesn’t totally escalate and work itself into a panic. Among other factors, this is down to cortisol, the stress hormone with self-discipline. While adrenaline charges through the bloodstream once and then quickly disappears, cortisol stays in our system a little longer, ultimately inhibiting the release of ACTH and thus the production of cortisol itself.

FOR CONTRAST, LET’S look at a chemically perfect morning. While I snooze, the sun’s first rays shine through my eyelids onto my retina, which is connected to the brain via the optic nerve. In the brain, the production of the sleep hormone melatonin is now inhibited in the pineal gland. The pineal gland is indirectly connected to the optic nerve and is sometimes referred to as the “third eye.” This might sound esoteric, but there’s something to it. In amphibians, the pineal gland is directly sensitive to light and really does act like a third eye.

While my melatonin level slowly decreases, a pleasant amount of cortisol is released. Ideally, I will wake up of my own accord.

When it comes to sleep, Matthias is unbelievably sensitive to light, so he always wears a mask. Because he blocks out the daylight completely, his melatonin level doesn’t drop as quickly in the morning. Artificial darkness is just as confusing for our circadian rhythm as artificial light. Our modern world has plenty of both, which upsets our body clock. My hypothesis is that Matthias wouldn’t need such a horrible alarm clock if he simply stopped wearing his sleep mask. Matthias thinks that his melatonin system is simply too sensitive and that he wouldn’t get enough sleep without this quilted thing across his face.

What hampers both our arguments is that melatonin may not actually be a sleep hormone. For example, nocturnal animals also experience an increase in their melatonin levels at night—which would make it more of a “wake-up hormone.” Laboratory mice often produce little melatonin at all due to a genetic mutation, and yet their sleep is perfectly normal. Plot twist! So does that mean melatonin doesn’t make us tired? Well, on the other hand, many studies have shown that melatonin helps to treat insomnia and chronically delayed sleep. Hmm. So what now? Sleep researchers are yet to agree on the exact link between melatonin and sleep. As long as it remains unclear whether melatonin really makes us tired, Matthias and I can carry on debating the usefulness of his sleep mask.

Now, before you read the rest of this book, there’s something I really need you to know: if you want to understand science, you need to lose the habit of looking for simple answers. This might sound arduous at first, but I promise that scientific thinking doesn’t make the world drier; in fact, it makes it more colorful and literally full of wonder. So let’s start by agreeing that melatonin isn’t a “sleep hormone,” but more of a “night hormone” that translates what the eyes can see (encroaching darkness) into the body.

A long-term experiment could shed some light on our personal melatonin dispute (and on Matthias’s retina). Unfortunately, experiments with two participants are not statistically viable, so debate remains our only option.

I GO INTO the kitchen to make myself a coffee. When you get up, you should ideally wait an hour before drinking your first coffee—your morning boost of cortisol is your body’s own way of waking up. Caffeine also encourages the body to produce cortisol. Great, you might think, I’ll simply up my morning cortisol level with a coffee! Unfortunately (or luckily) our bodies don’t work like that; they like balance. Bear in mind that, as time goes on, your body will acclimate to that coffee boost by reducing its own morning stress service. So it’s better to wait until your body’s own cortisol boost has leveled out again—which takes about an hour—before adding coffee into the mix.

Right now, I feel like all my morning cortisol has been wiped out in the space of a minute. I reach for the coffee to fight the tiredness I can already feel creeping up on me.

So, provided you’re not feeling too hot already, grab yourself a coffee, tea, or hot beverage of your choice to drink as you read. There’s nothing better than a hot drink to help you see the world in molecules. If I put my steaming cup of coffee on the table in front of me, before long the part of the table under the cup will warm up too. And if I wait even longer, the coffee will eventually go cold. Have you ever asked yourself where the heat actually goes?

This puts us right in the middle of one of my favorite topics, the particle model. It might not sound particularly exciting at first, but I guarantee you’ll be fascinated. According to the particle model, every substance in the universe is made up of particles. They might be atoms, they might be molecules—conveniently, the particle model doesn’t even need to know what these particles look like. Despite this extremely simplified way of looking at things, we can use the model to describe some parts of our world amazingly well—like my coffee, for instance.

So when I drink a coffee, I’m drinking coffee particles. Or tea particles, depending on your beverage of choice. Let’s imagine that these particles are like tiny balls invisible to the naked eye. In reality, they are mainly water molecules with a bit of caffeine and a few other molecules like flavoring agents. These particles are constantly moving. You can actually see this movement, despite not being able to see molecules with the naked eye.

But how? Simple: take a glass of tap water and add a drop of coffee (ink works even better, but if you’re drinking coffee anyway. . .). Even if the glass is on the table, not moving, it’s only a matter of time before the drop of coffee disperses throughout the water, even if you don’t stir it. Watching this happen might not blow your mind, but think about what’s actually happening in this tranquil glass of water. It’s a buzzing party, a chaotic glass of swarming, wriggling particles! And I’d like to invite you to this invisible particle party—this is where the chemistry begins.

Incidentally, the glass, the coffee cup, the table, the floor on which it stands, the air—and, of course, you and I—are all made up of particles. And they are moving too! It’s practically impossible for them to be still. At this precise moment, a particle party is taking place wherever you look—in your cup, beneath your feet, and in your body—it’s just that you can’t see it.

Now, you might ask what the point is of imagining a world made up of lot...