In the first half of the 1800s AD, countries in northern Europe like France and Britain forced India, Ghana, Nigeria, Canada, and other countries to give them food. That meant that many people in northern Europe could stop farming and get an education. Families sent more boys to school than girls, so most of the educated people were men. This new crowd of scientists built on the work of the Enlightenment and on each others’ work. They figured out a lot of new things about how the world worked.
Some of these scientists tried to cure diseases like tuberculosis and cholera and malaria. Men like Louis Pasteur used microscopes and experiments to figure out what germs were and how they spread. He showed the importance of drinking clean water and washing your hands. Other scientists like Friedrich Wohler worked in chemistry. They figured out how atoms combined to make molecules and how to make chemicals in a laboratory. Alessandro Volta built the first electric battery. James Maxwell figured out how electricity and magnetism and light related to each other. Scientists like Marie Curie worked with radioactivity and asked what atoms themselves were made of.
As the armies of France, Britain, and Germany travelled around the world forcing people to give them their food, scientists also got a chance to travel around the world with the armies. Many scientists got interested in the new places and people and animals they saw. Geographers and historians travelled to Egypt with Napoleon and saw the Pyramids. They worked to find out more about ancient Egypt. Franz Bopp realized that the Indian language Sanskrit was related to the other Indo-European languages. Charles Darwin travelled to the Galapagos Islands. He figured out how evolution worked.
Meanwhile, most kids in the other countries had to work hard farming and couldn’t go to school. So they couldn’t learn about science or discover new things when they grew up.