Joseph Black

Hello! My name is Joseph Black, and I was a scientist who loved solving puzzles about the world around us. I was born far from my family’s home, in a city called Bordeaux in France, on April 16th, 1728. Even though I was born in France, my family was Scottish, and when I was a boy, we moved to Scotland. I was always asking questions and loved to figure things out, so I knew I wanted to study medicine and science. In 1744, I went to the University of Glasgow, which was a very exciting place where my journey of discovery truly began.

When I was a student at the University of Edinburgh, I became fascinated by a chalky powder called magnesia alba. I really wanted to know what it was made of. Around the year 1754, I decided to find out by doing many careful experiments. I discovered that when I heated this powder, or when I added acid to it, it released a special kind of gas. This gas was different from the air we breathe! I called it 'fixed air' because it seemed to be 'fixed' inside the solid material. This was a very big discovery because, at the time, most people thought there was only one type of air. The gas I found is what you now call carbon dioxide!

After I became a professor in 1756, I turned my attention to studying heat. I noticed something peculiar when I heated a block of ice. I watched as the ice slowly melted into water, but its temperature didn't change at all, even though I was adding more and more heat! It was a real puzzle. I realized the heat was 'hiding' inside the water as it changed from a solid to a liquid. Around 1761, I came up with a name for this hidden energy: 'latent heat.' This discovery explained why it takes so long for a snowy day to warm up, even when the sun is shining brightly on the snow.

In 1766, I became a professor at the University of Edinburgh. During my time there, I had many clever friends, including a brilliant inventor named James Watt. James was working on improving the steam engine, a very important machine that used steam to power other machines. My discoveries about latent heat were exactly what he needed! Understanding how hidden heat worked helped him design a much better steam engine that used less fuel and was more powerful. His invention helped change the world, and I was proud that my scientific curiosity could help my friend achieve something so great.

I spent the rest of my life teaching and sharing my love of science with my students. I lived to be 71 years old. Today, I am remembered as one of the first chemists to use careful measurements in my experiments, which helped make chemistry a more exact science. My discoveries about carbon dioxide and heat helped other scientists understand our world in a whole new way and helped power amazing new inventions that shaped the future.