Emilie du Chatelet's rich father, who was interested in literature and science, hired tutors to homeschool her, instead of sending her to a convent school. She learned Latin, German, Greek, and Italian, as well as math and science.
When du Chatelet was 18, she married an older and richer man, and they soon had three children, though the youngest died when he was a baby. After the kids were born, in 1733, du Chatelet started working on math again, learning algebra and calculus. Around this time, she also became the philosopher Voltaire's girlfriend.
Voltaire had just come back to France from England, where he had learned about Issac Newton's work in physics, and about Locke's work in philosophy. Like Astell a little earlier, du Chatelet criticized Locke's ideas. Locke had said that scientists should start from their observations, but du Chatelet argued that scientists should work to understand underlying principles and laws, like Newton's Laws of Motion, to get at the truth.
Also like Astell, du Chatelet pointed out that the reason women didn't make scientific discoveries or write great plays was not that women were stupider than men, but that they didn't get to go to school. She suggested that the King, Louis XIV, could make his country much richer by educating women instead of wasting their brains on flirting and clothes.
Du Chatelet proposed an experiment to show whether different colors of light carried more or less heat. She suggested using a glass prism to create a rainbow, and then placing thermometers to measure the heat of each color of light separately. This would have worked to show that longer wavelengths of light - like red - do warm things up more than shorter wavelengths - like blue. But du Chatelet never did her experiment.
A little later on, du Chatelet proved that the energy of a moving object is not proportional to its velocity, as Newton and Voltaire had thought, but to the square of its velocity. Du Chatelet translated Newton's work from Latin to French, and wrote a valuable commentary on it. She also wrote about what happiness was. She suggested that one path to happiness was through being famous, and that for women, who couldn't fight in battle, the best way to get famous was scientific discoveries.
Then when du Chatelet was 42 years old, she had another baby with another boyfriend. It was very risky to have a baby at that age, and she died a week after the baby was born. A few months later, the baby died too.