Because arteries and arterioles become less elastic as people age, they cannot relax as quickly during the rhythmic pumping of the heart. As a result, blood pressure increases more when the heart contracts (during systole)âsometimes above normalâthan it does in younger people. Abnormally high blood pressure during systole with normal blood pressure during diastole is very common among older people.
Then in 1897, Thompson discovered the first component part of the atom: the electron, a particle with a negative electric charge. Discovery of the Atom. By the 19th century, technology had advanced greatly and many elements had been discovered to work with.
He improved Democritusâ first theory. He discovered that atoms of different elements are different from others, and that atoms of the same element are the same size. He also discovered that atoms combine in specific proportions and that all substances are made of atoms. To find this out, he worked with gases.