Category Science

William Harvey was an English physician who lived in the 17th century. He was the first person to correctly describe blood’s circulation in body.

       He showed that arteries and veins form a complete circuit starts at the heart, and leads back to the heart. He also established that the heart’s regular contractions drive the flow of blood around the whole body.

        Before his discoveries, blood was thought to ebb and flow through the body by the contraction of arteries. Harvey’s knowledge came from observations he made of blood flowing through the veins and arteries of living animals that he cut open. This may seem cruel, as there were no anaesthetics in Harvey’s time.

        Nevertheless, it is how we arrived at an understanding of blood and its circulation in the body.

       William Harvey’s work also laid down the foundations of physiology, which is the study of body functions. 

Joseph Black, a British chemist and physicist, is famous for his discovery of carbon dioxide. Black was always a meticulous chemist, keeping careful note of all his results and measurements. It was this which led to his discovery of carbon dioxide.

      Black also took an interest in the science of heat. In the 18th century, there were several competing theories about the nature of heat, and how it related to temperature.

      Black’s investigations not only clarified the distinction between temperature and heat, but also resulted in the theory of latent heat. Black was gifted and effective teacher. His course in chemistry proved so popular that many students, even those with no particular interest in the subject, were eager to attend.

     Alongside his teaching, black carried on an active and demanding medical practice. Joseph Black, widely respected both as a scientist and a physician, is truly one of the titans in the world of science.

Joseph Priestly, an Englishman is noted for his groundbreaking contributions to experimental chemistry, electricity, and the chemistry of gases.

       Before him, scientists thought that the air on earth consisted of carbon dioxide and hydrogen. Priestley brought 10 more gases to this light, such as nitrogen, hydrogen chloride, carbon monoxide, nitrous oxide and oxygen.

       He isolated oxygen in its gaseous state, and conducted a series of experiments to distinguish each gas based on its properties. Priestley also made another discovery that has been highly appreciated by surgeons worldwide. He discovered nitrous oxide, which was also known as laughing gas. It was the first surgical an aesthetic to be used.

      Priestley’s best known achievement in the field of biology in 1772 was his work with photosynthesis. Priestley’s other interesting discoveries include the fact that graphite is a good electric conductor, and that gummy tree sap is a good eraser for pencil marks.

      Did you know that you can enjoy your favorite fizzy drink thanks to Joseph Priestley, for he was the one who invented soda water?

The English scientist Henry Cavendish was an experimental chemist and physicist par excellence. Cavendish was the first to recognize hydrogen gas as a distinct substance. He called it inflammable air.

         Cavendish showed that hydrogen is much less dense than air. In 1785, he published a paper showing the earth’s atmosphere consists of four parts nitrogen to one part oxygen.

         In addition, to his achievements in chemistry, Cavendish is also known for the Cavendish experiment. He was the first to measure the force of gravity between masses in a laboratory, and to produce an accurate value for earth’s density.

       Henry Cavendish also experimented with electricity, but much of his work on the subject was only published after his death. He was renowned for the great accuracy and precision of his scientific research.