Everything is made up of matter. Matter is anything that takes up space and has mass. Anything that is material is made of matter Ц in fact both words come from the same Latin root meaning Ђstuffї. Matter is made up of molecules, and molecules are made up of atoms.
About 2400 years ago, a Greek philosopher named Democritus (460-370 B.C.) thought a lot about what things were made of. One day while slicing an apple, he wondered how small he could slice it. He figured that everything that could be touched could be divided again and again until there was a piece left that was so small it couldnТt be cut. It turns out that he had the right idea, and that smallest piece we now know as the atom. The word atom comes from an ancient Greek word that means Ђuncuttableї. Democritus could not see an atom (as we can today), but he had figured out something very important. His atom is what we talk about today as an element. In the mid-17th century, scientists began to prove the existence of specific elements, or pure substances that couldnТt be Ђcutї into other pieces. This led scientists to discover the elements and atoms that make up all matter. At the beginning of the 20th century, scientists found that DemocritusТ atom actually could be cut into smaller pieces, called sub-atomic particles.
The parts of the atom are nucleus, electron, proton and neutron. The nucleus is at the center of the atom. It is made up of protons and neutrons. Moving around outside of the nucleus are the electrons. In 1915 a scientist named Niels Bohr proposed a model of the atom that illustrates the atomic structure, called the planetary model or the Bohr model. Proton comes from the Greek word for Ђfirstї. Protons have a positive charge. Typically, positively charged particles would repel each other, but they are held together in the nucleus with a force called the strong atomic force. This is the strongest force in the universe. The other part of the nucleus is the neutron. Neutrons are about the same size as protons. The word Ђneutronї comes from the Latin word for Ђneutralї. The neutron has no charge Ц it is neutral. The third particle of an atom is the electron. Electrons are much smaller than the protons or the neutrons (almost 2000 times smaller). It is easy to illustrate them orbiting around the nucleus using the Bohr model, although they actually move in a cloud. Electrons are negative. Protons and neutrons are both composed of other particles called quarks and gluons. Protons contain two Ђupї quarks and one Ђdownї quark while neutrons contain one Ђupї quark and two Ђdownї quarks. The gluons are responsible for binding the quarks to one another. (From www.wikipedia.org)
THE THEORY OF RELATIVITY
ЂWhen you are courting a nice girl an hour seems like a second. When you sit on a red-hot cinder a second seems like an hour. That's relativityї.
|according to Цв соответствии с, согласно advance (N) Ц успех, достижение contradictory (N) Ц противоречащий contraction (N) Цсокращение consequence (N) Цследствие, вывод, заключение curve (V) Цгнуть, изгибать; (N)крива€ curvature (N) Цкривизна, изгиб, искривление disagree (V) Цне совпадать, расходитьс€ encompass (V) Цокружать, заключать equation (N) Цуравнение, равенство exert (V) Цприводить в действие, оказывать давление, вли€ть expand (V) Ц расшир€ть inertial (Adj) Цинерционный incompatible (Adj) -несовместимый increase (V) Цувеличиватьс€ instead of Цвместо, взамен observer (N) Ц наблюдатель postulate (N) Цаксиома, постулат precess (V) Цпредвар€ть, предшествовать propose (V) Цпредлагать, предполагать||regardless of Цне обраща€ внимание, не взира€ на shape (N) Цформа, образ, модель simultaneity Цодновременность slow down (V) Цзамедл€ть source (N) Цисточник space (V) Цпространство, рассто€ние (между двум€ объектами) spacetime Ц пространство-врем€ suck up (V) Цвсасывать, поглощать the Special Theory of Relativity Цспециальна€ теори€ относительности the General Theory of Relativity Цобща€ теори€ относительности time dilation Цраст€жение времени transmutable (Adj) Цизмен€емый, превращаемый uniform (Adj) Цравномерный, посто€нный upshot (N) Цразв€зка, результат vacuum (N) Цбезвоздушное пространство, пустота well (N) Цколодец, скважина with respect to Цчто касаетс€|