Her two younger brothers stay behind in their village, Kharaghoda, a chaotic mix of camels and water buffalo, schools and vegetable sellers, newborn babies and blind old men.
Though the village of 12,000 is a seven-hour walk from Jyotsna's isolated hut on the salt pans, it might as well be England, it feels so different and far away.
"It's easier to be a boy," said Jyotsna, who was forced to drop out of school at 10 to help her parents. "They get to go to school."
Jyotsna's mother said she could not afford to let all three of her children study, so she picked her daughter to work. It is a familiar story in much of the developing world, and particularly South Asia. In India, half the women older than 15 are illiterate, twice the rate for men, and millions of poor girls are pulled out of school to help at home, often when they are 10 to 12 years old.
"I regret she has this hard life," said her mother, Ranjanben Patadia, 35. "But this is the destiny of girls. It was my destiny, too."
Unlike her mother, who never set foot in a classroom, Jyotsna did study on and off for a few years, thanks to a major government effort over the past decade to enroll all children. Though Jyotsna can still barely read or write, that progress has made her more aware of what she is now missing.
Human rights advocates say millions of teenage girls like Jyotsna are less resigned than their mothers were to the age-old preference in India for sons.
"Boys have more options," Jyotsna said one recent day as she tidied the one-room hut where she spends most of her time. She is told she is too old to play running games, yet notes that boys her age can.
Boys freely come and go, she said, but once girls reach puberty they are kept close to home, another reason that the start of a girl's menstrual period often means the end of her schooling.
"I would like to learn more," said Jyotsna, whose name means moonlight. She said people gossip that older girls who go to school "are too outgoing." But if she had more education, she said excitedly, "I would talk in front of 50, even 100 people!"
* * *
To this day, in some parts of India, fewer than eight girls are born for every 10 boys, because parents abort female fetuses, a legacy of a centuries-old mind-set that values boys more. Sons carry the family name, inherit land and become the main breadwinners.
In this patriarchal society, fathers and brothers are widely seen as the decision-makers, many even telling wives and sisters what to cook and when to leave the house. Especially in rural India, girls are far likelier to die before age 5, because scarce food and medicine are given first to their brothers.
"The constitution says, yes, women are equal, but society says, no, they are not," said Veena Padia, program director in India for the international aid group CARE. "We really feel angry and frustrated, at times even disgusted," at the bias against women, she said. "Mind-sets take a long time to change."
Padia said that middle- and upper-class women have made significant advances and that it is poor and marginalized women who suffer the greatest discrimination.
There are so many girls like Jyotsna in the salt pans, working while their brothers study, that CARE is supporting Ganatar, a local group that digs pits and covers them with burlap roofs to serve as makeshift classrooms. The hope is that parents might send their daughters to school if it were closer.
When girls marry, as Jyotsna is expected to soon, they move in with their in-laws. Many view it as a bad investment to spend scarce cash on pencils and notebooks for a daughter who will work most of her life for her husband's family.
"They call it 'watering somebody else's garden,' " said Susan Durston, an education adviser with UNICEF.
Long-standing social customs and beliefs bar girls from school in many parts of South Asia.
In Bangladesh, "Eve-teasing" -- bullying and sexual harassment -- hounds girls from class. In Afghanistan last month, Muslim extremists threw acid in the faces of girls walking to school as a warning to stay home. Zealots in northwestern Pakistan recently torched 150 schools for girls.
Usually, though, a quieter discrimination steals a girl's chance to learn. Every day, parents decide, for instance, to buy a bicycle so their son can get to school but refuse to spend money on a book for their daughter.
* * *
Jyotsna's brother Bharat, 13, bounced out of bed in a house that has everything Jyotsna's hut does not: electricity, a television, plenty of water, cousins dropping by.
After filling up on steaming tea and warm millet bread his grandmother served him, Bharat dressed in a spotless blue-checked shirt and blue pants and ran out the door into a dirt street filled with rickshaws and a buzz of laughter and life.
It was 7 a.m. and time to go to the Kharaghoda public school, just across the road.
When the bell rang in the courtyard, Bharat and others lined up to sing the national anthem. One boy beat a drum, two others clashed cymbals. Hands at their sides, the students stood in front of a picture of Saraswati, the Hindu goddess of knowledge. There were 60 boys and 30 girls.
A 10-year-old girl named Hiral straggled in late, holding the hands of her brother and sister, ages 3 and 5. They would sit beside her all day in class, a practice teachers allow to encourage girls to come to school even when their parents make them babysit.
Bharat had no such distractions.
At 8 a.m. sharp, with his thick black hair combed neatly and his eyes bright and eager, he sat near the window in Classroom 4 reading about how India won its independence in 1947.
His room, in a century-old building that was once a jail, ached for paint. It is not that anyone here has much, human rights advocates say, but rather that what little there is so often goes to boys.
In Bharat's class there were 21 boys and nine girls. The male teacher -- many elementary school teachers in India are male -- spoke near a poster with pictures of 24 Indian leaders. With the exception of Indira Gandhi, all were men.
The teacher, Surendra Zala, lectured about British colonial rule. Speaking in the local Gujarati language, he told his students it was important to learn English, "because you need it to be connected to the world and the Internet."
Bharat listened intently, neatly jotting down notes. His cotton book bag bulged with 29 workbooks and notepads. History is his favorite subject, and Mahatma Gandhi is his hero because he "won independence peacefully," he said later.
Geometry was next, and then recess, when Bharat stopped drawing rectangles and ran toward a wobbly aluminum slide in the dusty schoolyard.
In English class, he pulled out his notebook full of random sentences: Dev plays cricket. Meet my friend Pittu. There is a peacock in the garden.
A cooling breeze drifted in through the classroom window.
* * *
Clack. Clack. Clack. The "machine," as everyone calls their water pump, sounds like a heartbeat. And in a way, it is. If it stops, so does life here. No more salt, money, meals. Jyotsna's parents earn $500 annually from mining salt, and that all depends on the rickety old pump sucking briny underground water to the surface.
Once there, the water is channeled into hand-dug ponds. The sun bakes it, and the salt crystals left behind are sold to flavor potato chips and scrambled eggs in distant lands.
One of Jyotsna's chores is to make sure that the machine, just outside the family's hut, keeps clackity-clacking. Sometimes it overheats or the fan belt breaks. Jyotsna then signals for help by holding a mirror up to the sun, creating flashes of light, and her parents come running.
At 6 one recent morning, Jyotsna had her breakfast: a cup of black tea. Milk doesn't exist in this place with no refrigeration. She brushed her brilliant white teeth with a toothbrush she keeps in a cranny in the dried-grass wall. There is no sink, no toilet.
Her parents had left before sunrise. They earn 35 cents for every 220-pound bag they fill with salt, so they start early and work late.
Dressed in a saffron-colored salwar-kameez, her bead necklace held together with a safety pin, Jyotsna folded the covers on her parents' cots. She sleeps on a thin bed of blankets in the dirt.
As daylight broke, she swept. The night's wind, as always, had blown back the caked mud she brushed away the day before. Her tiny 4-foot-10 frame bent at the waist, she tidied her patch of the plain, again.
By mid-morning she had warmed the previous night's lentils, bread and other leftovers and carried them to her parents for breakfast, a water jug balanced on her head.
Her parents struggle in the heat, and her father, Bhopabhai Patadia, 39, sometimes collapses. He has high blood pressure, as do many people here, because too much salt seeps into his body through cracks in his bare feet.
"I have the same problem," Jyotsna's mother said. "But I don't take medicine. We can't afford medicine for everyone."
In the evening sometimes, her husband smokes a bidi, a cheaper version of a cigarette. It's an indulgence, his wife explained, that "is only for men."
Jyotsna's father handed his daughter his empty water cup with a kind nod but not a single word. Then he and his wife began another shift in the unrelenting sun.
"No, it's not fair" that young boys study and girls work, he would say later. "But what can we do?"
Back at the hut, after washing the dishes, Jyotsna put chilies on a stone and ground them into a red paste, an hour's work, the start of another meal.
* * *
By noon, Bharat was home again, eating spicy bread flavored with chilies and vegetable curry.
"I will do my homework later," he told his grandmother as he flipped on the old black-and-white TV set. It was too hot to play cricket, his passion, he explained, so he lay on his bed to watch TV, his hands behind his head.
It was cool inside; he didn't bother with the overhead electric fan as he watched a show about the Hindu deity Lord Krishna, interrupted by a blaring ad urging people to buy gemstones corresponding to their zodiac signs.
Any chores to do today?
Bharat shook his head no.
"The boys don't do anything. Just eat and play," said his grandmother, Shanti Patadia. "We have to teach the girls how to work in a house because they will get married, but the boys don't even know how to sweep."
"If a boy would do all these things in the house, people would think he is girlish," his grandmother said. "People would laugh."
Bharat said he misses Jyotsna, especially at mealtimes. "If she were here," he said, "she could help with the cleaning and cooking."
Next year, Bharat will ride his bicycle to the secondary school, farther away, where there are three boys for every girl.
"I hope the boys still talk to me when they become government workers," Shanti Patadia said, delighted at the idea her grandsons might one day have a handsome salary and easier lifestyle.
As for Jyotsna, she said, with a grandmother's knowing look, "In a year or two, we will get her married."
* * *
As the sun burned in the afternoon sky and turned these barren plains into a flat oven the size of Rhode Island, Jyotsna clung to the shade around her hut, sweeping, cooking and washing.
The nearest neighbor is a mile away; families live apart so their pumps aren't competing for the same salty water. Her brothers hear news at school and on TV. She did not know that all of India had just celebrated a successful lunar mission and planted its flag on the moon. She had never heard of Barack Obama.
"If I had a choice, I wouldn't marry," she said, her eyes tearing, as they often do when she talks about what life will bring her next.
As she pulled a few more onions from a burlap sack, she said she daydreams of cooking like a chef she once saw on TV: "I dream I can buy the ingredients and know how to write down the recipes."
She said she could copy words from a blackboard but is unable to write down words she hears spoken.
"My brothers, they will study. They can hope for different things," she said. "What can I be?"