One of the first experiments we give children teaches the three states of water: liquid, vapor, and ICE at the border storing children in hieleras, short-term detention facilities known as iceboxes because it’s so cold you can see your breath as it transforms from vapor into liquid and ice.

Why? a child on the floor asks.

Our bodies are mostly water and the water inside them is the same temperature as our bodies, around 98.6 degrees, but the icebox is much colder so when a child exhales a warm, saturated breath, it becomes dew, and when it is cooled even further, condenses to minuscule droplets of liquid and ice, and this, child, is the cloud we see.

Some children are given two apples a day, which helps them keep time.

When it comes to the human bones, it’s hard not to admire the rib cage that holds my heart like it’s an animal.

Still, if I had to name just one favorite, I’m torn between the hip and the jaw.

Imagine the invention of the wheel and then the waterwheel, the color wheel, the spinning wheel for turning threads into blankets.

Next lesson: there are five basic needs—water, air, food, sleep, shelter.

I admire the moving parts.

The evolution of the hip decoupled walking from breathing so we can run at sunset toward each other or away from fire.

The bones of the hips are winged; if I flashed a picture quickly before you like pornography, you might mistake it for an emperor moth, which is one way to enter the world, headfirst through a body attracted to light.

The history of hips frees the hands for holding a baby, rocking a baby, holding your child’s eyes near your eyes at the distance the eyes first can see.

The jawbone gives us each a face.