Explain the characteristics of the quantum world (quantum physics) that we normally wouldn't see in the classical world.
Quantum physics deals with the characteristics of matter and energy at subatomic levels. The properties exhibited by particles that lie in the realm of quantum physics and by those that lie in the realm of classical physics is the same. The differences that arise between the two is due to the fact that in classical physics it is possible to make approximations and explain characteristics without introducing a substantial degree of inaccuracy.
For example, the uncertainity principle in quantum mechanics states that it is physically impossible to know both the position and the momentum of a particle at the same time. The position of a particle is measured by bouncing off electromagnetic radiation from it and measuring the time taken by it to return. If one desires to measure the position of a particle with a higher degree of accuracy it is essential to use radiation with a lower wavelength. As the wavelength of electromagnetic radiation is decreased, there is an increase in frequency and subsequently an increase in energy. When radiation bounces off the particle a part of the energy is transmitted to the particle which alters the momentum of the particle. The attempt to accurataly measure the position of a sub-atomic particle itself changes the momemtum randomly by a very large extent.
In classical physics effects like the one just descibed can be ignored as the momentum of a large particle is affected to a very insignificant extent irrespective of the frequency of radiation being used to measure its position.
Classical physics is essentially the same as quantum physics. The differences in characteristics between the two is due to the fact that it is not possible to make the approximations that are allowed in classical physics due to the extremely small mass and size of the particles.