Introduction to the Universe - Essay Example

The study of the interior of the earth uses seismic waves. They are P-waves and S-waves. P-waves are longitudinal and, thus, can travel through solids and liquids. S-waves are transverse. Thus, they can only travel through solids. P-waves also travel faster than S-waves. Geologists use these properties to study the internal structure of the earth. When the seismic waves pass through different layers, they get refracted. The same waves undergo reflection when they hit hard surfaces at certain angles. Seismometers located at various parts of the earth record the occurrence and properties of the seismic waves. The data can then be analyzed to ascertain the properties of the elements of the earth’s interior. In the analysis, the data recorded by seismometers are used to determine the distribution of P-waves and S-waves. In a region where the seismometers detect P-waves but not S-waves, it can be inferred that molten materials must have intercepted the S-waves. Thus, geologists use known properties of waves to study the internal structure of the earth (Indiana.edu).
Atoms have negative electrons that orbit around a nucleus that is positively charged. The nucleus has electrically neutral neutrons and positively charged protons. An atom has equal protons in the nucleus as the number of orbiting electrons. An atom in such a state is said to be electrically neutral. The protons determine the element that the atom represents. Bohr’s atom model was an early attempt that explained how atoms produce absorption and emission line spectra. An atom’s normal condition is when it possesses minimum energy at the ground state. An orbiting electron can escape from the atom when given enough energy that is then termed ionized. An atom can also absorb an atom from neighboring atoms. Between the atom and ion states, the electron remains in the excited stated with a specific amount of energy (Rogers, 2008).