Experiment

The winter rain fell in a steady, dreary drizzle. This small southern city would likely see no snow this year. Whether due to global warming or the urban heat island effect, the scenes of winter from my childhood—the goose-feather snowflakes and the icicles hanging from the eaves at my grandmother’s old home—now existed only in memory. All that remained was this damp, biting, incessant rain.

The class representative secretly turned on the air conditioner, but in a classroom this large, the tiny machine’s warm breeze was utterly useless. If the cold in the north is a physical attack, then the cold in the south is a magical one. The fine, misty rain seeped into everything, creeping into collars and sleeves; you wouldn't feel it at first, but given enough time, you would be frozen from the inside out, from head to toe.

During the break, the boy in front of me secretly ate spicy snack strips under his desk. The surrounding students caught the scent, and one by one, they reached over; within minutes, the bag was practically picked clean. He didn't seem annoyed, shaking the nearly empty bag as he turned around. "Do you want one?"

"Oh? Asking me? Thanks. It’s just... the smell is really quite strong." This smell, this scene—it felt like being back in elementary school.

"Hahaha, sorry—I’m just using magic to fight magic. In this kind of wet, freezing weather, you have to ignite the fire in your heart with spicy strips to survive!"

*Chuunibyou.* Beyond saving.

When school ended, Ling Quan didn't have an umbrella. The folding umbrella stuffed in my backpack wasn't large, and two people huddled together could barely keep the rain off.

"So cold, so cold," I said, stomping my feet and blowing into my hands. "The temperature is practically the same as the last two days, but it suddenly feels so much colder... I feel like a human psychrometer."

"No... wait, that’s not right. In summer, the higher the humidity, the hotter it feels because sweat evaporation slows down. So why does higher humidity make it feel colder in winter?"

"Well..." Ling Quan pondered for a moment. "You have to grasp the primary contradiction."

"To maintain body temperature, in summer we rely on sweat evaporation to dissipate heat, while in winter we rely on wearing more clothes to stay warm... or rather, relying on 'wearing more air' to reduce heat transfer to the outside."

"Heat transfer occurs in three ways: convection, conduction, and radiation. Let’s ignore radiation for now... If you stood outside in the dead of winter naked, the first thing that would happen is heat conduction from your skin to the air."

"Isn't the first thing that happens getting sent to Wutaishan (a nearby psychiatric hospital)?"

"Then, the layer of air heated by your body convects with the cold air outside, and the heat is carried away," Ling Quan ignored me, continuing her explanation. "Once you have clothes on, it becomes heat conduction from the skin to the clothing, and then from the clothing to the outside." She patted her own bulky black cotton-padded jacket. "The thermal conductivity of air is very low; it is a poor conductor of heat. Wearing a cotton jacket or a down coat essentially uses the fluffy structure of those fibers to trap a layer of air that is difficult to convect, which keeps you warm. But in this devilish weather—the heat conduction between the ice-cold rain and your skin, plus the water vapor getting into the clothes and condensing on the fibers, causing its three-dimensional structure to collapse..."

"It 'can't hold itself up' anymore, right?"

"Exactly."

I switched hands on the umbrella and tucked my frozen hand into my pocket.

"I’ll hold it." She grabbed my hand and snatched the umbrella away.

"Wait, I understand the logic, but why are your hands still so warm?"

"I’ve got heat packs stuck to my cuffs, my ankles, and my stomach," she said with a mischievous grin. "Do you want one?"

I felt a bit shy about taking it, but thinking about the twenty-minute ride on the damp, unheated bus ahead, I accepted it.

"Thanks—hey, let me walk you a bit further."

"No need, the rain isn't that heavy. What if you miss your bus?"

I insisted on following, and she didn't refuse again.

After walking about a hundred meters, we arrived at her apartment complex. It was quite close to the school; I was a little envious.

"This is as far as you go, hurry back—if my mom sees someone walking me home and mistakes you for a boy, I’ll never hear the end of it! Bye!" With a turn of her head, Ling Quan broke into a hundred-meter sprint and vanished into the rain.

It was just a heat pack, but I found myself reluctant to open it. I... didn't want to let the chemical energy of such a large packet of reduced iron powder be irreversibly converted into thermal energy so easily, I told myself.

Our second club meeting was held in the biology lab on the third floor of the science building.

"Sorry everyone," the vice president sat on the lecture platform with his legs crossed (doesn't the faculty advisor mind you doing that?), "I originally wanted to make something this semester—it was going to be fruit wine—but this temperature isn't really suitable, so we’ve moved it to next semester. So, this time, we’ll use the school’s microscopes to observe some things and try some hand-cutting sections. You’ll have to take tests on this in your senior year anyway, so learn it now and you can act cool in front of them later."

"Now... get into pairs, one microscope per pair. We’ll go over some preparatory knowledge for showing off first."

"The basic structure was in the first-year textbook. Base, mirror—the school’s are quite advanced, there’s an illuminator underneath, just press this to turn it on. Objective lens, nosepiece, body tube, eyepiece. Multiply the objective by the eyepiece for total magnification."

"Besides magnification, there is another very important parameter for microscopes called resolution, which refers to the minimum distance between two points that it can distinguish. The formula is D = (0.61λ) / (Nsinθ)."

At this, Ling Quan raised her right hand high.

"What is your question?"

"Where does that formula come from?"

"Uh... anyway, physicists did a series of calculations and derived that formula—don't ask me any further, I don't know! This is the Biology Club, not the Physics Club!"

Ling Quan nodded, letting the senior off the hook.

"Right... where was I..." The vice president flipped through his notes, looking like he had actually prepared quite a bit. "The resolution of a light microscope is about 0.2 micrometers, and microscopes made using electrons instead of photons have a resolution of about 2 nanometers—don't tell me there's someone who doesn't know about wave-particle duality..."

The club president, sitting in the front row, raised his hand.

"What is it now?"

"Can we start the experiment early?"

"..."

The vice president slapped his notes against his head, turned around, and pulled a plastic bag from a bag behind the podium, filled with various flowers and plants.

"Everyone come up and take some. This is spinach, bought from the market yesterday. You can tear the leaf obliquely until you get a bit of the transparent lower epidermis with some green mesophyll, and then you can put it under the slide. You can also make sections; there are knives here. These are flowers the teachers didn't want; I saw them in the trash can after class and picked them up. Carnations and lilies—one is a dicot from the Caryophyllaceae family, the other a monocot from the Liliaceae family. Look at whatever you want... ask the advisor if you have questions."

I ran up to grab slides and coverslips, placing them in a white porcelain dish. I picked two spinach leaves and a carnation leaf, and took a lily flower. "Hmm... how do I do this?" I really wasn't familiar with this equipment.

"...First... make a slide of the spinach leaf’s lower epidermis?"

I tore a piece of spinach, relying on my memory of the biology textbook to drop some water onto the slide before placing the coverslip on top. The eyepiece was 10x, so I used the 10x objective lens and turned the coarse adjustment knob.

"I see it!" Like a traveler entering a new world, I shouted with excitement.

"What do you see! Let me see!" Ling Quan pushed me away from the eyepiece, turned the objective to 40x, adjusted the fine focus knob, and gazed greedily at the scene below.

"Colorless epidermal cells, green spongy tissue... and stomata! But I can't see the chloroplasts..."

"What should we look at next?"

"The carnation leaf is quite thick; it looks like it could be used for a cross-section."

Ling Quan pinched the leaf with the thumb, index, and middle fingers of her left hand, used her right arm to guide the knife across it a few times, and then used a small brush to sweep the slices off the blade and into a drop of water.

"The distinction between the palisade tissue and the spongy tissue doesn't seem very clear... but you can see the vascular bundles. Still, the cuts are a bit uneven..." Ling Quan muttered while looking.

"That kind of thing takes practice; you'll get better after doing it more. You can wedge thin leaves into a potato to cut them," the teacher's voice came from behind us.

I leaned in to take a look as well.

"Don't keep one eye closed."

"Oh, oh, right."

We moved the slide back and forth, and the class flew by.

"I want to see a cross-section of the lily anther! I’ve seen it in the book, and now I want to see it with my own eyes!"

I took the anther. "It’s already split open; can we still use it?"

"Hmm..." Before Ling Quan could answer, the teacher started calling for us to clean up and return the lab to its original state.

How interesting. I wanted to stay in the lab for the whole day. I thought, feeling a sense of reluctance as I cleaned up.