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.
The Discovery of the Electrons [edit]. The Electron was discovered in 1896, by the British physicist J. J. Thomson, using a cathode rays while doing discharge tube experiments. Thomson also determined e/m, ratio of the charge e to the mass m of the material particle which constituted these rays.