Electric Potential
Battery and Load In an electrical circuit, the battery maintains a voltage difference to allow current to flow through the circuit. In an electric circuit, the place where energy is consumed is called a load. Generally, … more
Buoyancy: Archimedes and the Crown
Why is the submerged volume important to understand buoyancy? It is so famous that the 3rd-century Greek philosopher Archimedes shouted “Eureka!” and ran out of the bathhouse naked. （What did Archimedes find out? – Quotations from … more
Ionic Bond
Formation and energy of the ionic bonds Metal atoms have strong properties to lose electrons and become cations. On the contrary, non-metallic atoms have strong properties to obtain electrons and become anions. As these two particles … more
Rutherford Scattering and Size of Nucleus
Discovery of nuclear At the beginning of the 20th century, there was little known about the structure of atoms except that they contained electrons. At that time, the atom was known as a pudding model containing … more
Temperature and Reaction Rate
Heat and molecular motion Every object is made up of atoms or molecules that are small particles that the eye can not see. These particles are constantly moved or oscillated themselves. This is called molecular motion. … more
Pascal’s Principle
Pascal’s Principle Pascal’s principle is as follows. “Suppose a closed tube filled with uncompressed fluid. Then, the pressure of this tube’s inside is the same everywhere.” For example, If you press any part of the tube … more
Projectile Motion
Projectile Motion When you throw an object, the object falls with a certain curve. The object performs a parabolic motion. This is a motion on a two-dimensional plane, not a straight line. To understand this movement, … more
Spectrum of Hydrogen Atom
Spectrum of hydrogen At the time of Rutherford’s experiments, chemists analyzed chemical components using spectroscopy, and physicists tried to find what kind of order in complex spectral lines. For example, a hydrogen arc tube containing hydrogen, … more
Total Internal Reflection and Optical Fiber
Total reflection and critical angle When light enters from a medium with a large refractive index to a medium with a small refractive index, the incident light does not pass through the boundary surface but is … more
Geometric Series
Geometric sequence is The geometric sequence is a sequence in which each term has a constant(common) ratio to its preceding term. For example, the geometric sequence with the first term ‘a’ and the common ratio ‘r’ … more