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 did an expirement that involved shooting a beam of particles at a thin sheet of gold. Through this he discovered that there is a small, dense, positively charged nucleus; most of an atomâs mass in the atomâs nucleus; atoms contain mostly empty space; electrons move in empty space in the atom.