Quantum Physics Explained in Simple Terms

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Every science student knows something about quantum physics, but not every one of them can explain it. If you are an H2, JC or A level physics student, it is important for you to have a good understanding of the topic because modern science is incomplete without it. By enrolling in physics tuition, you can also have a better grasp and a deeper understanding of the topic. So let’s start with the meaning of quantum physics.

What is quantum physics?

Quantum physics, as you may already know, is the study of the behaviour of matter and energy at the smallest levels – molecular, atomic, nuclear and even smaller. This branch of physics was necessitated by the discovery of the fact in the early 20th century that the laws of physics that govern matters of macroscopic scale do not function in the realm of microscopic objects. Quantum is a Latin word which means how much. In modern physics, it is used to refer to the smallest possible discrete unit of matter or energy that can be predicted and observed by various means.

Who developed the quantum theory?

Quantum theory was first proposed by Max Planck in his paper on blackbody radiation which he had presented to the German Physical Society in 1900. When seeking to discover why radiation from a glowing body changes in colour from red to orange to blue as it becomes hotter, he found that the question could be answered by assuming energy exists in individual units in the way that matter does and was, therefore, quantifiable.

To prove his theory, Planck wrote a mathematical equation involving the smallest possible unit of energy, which he called “quanta”. With this equation, he successfully explained that energy from a glowing body occupies different areas of the colour spectrum at different discrete temperature levels. He was awarded the Nobel Prize in Physics in 1918 for his work.

In 1905, Einstein added another brick to the theory by theorizing that not just the energy but radiation was made of quantas. In 1924, physicist Louis de Broglie proposed that at the atomic and subatomic level there is no fundamental difference in the composition and behaviour of matter and energy. He said that they both behave as if they were made of either waves or particles. This theory is called the principle of wave-particle duality.

In 1927, physicist Werner Heisenberg proposed that it was impossible to measure two complementary values, such as the moment and position of a subatomic particle. This theory is called the uncertainty principle.

Later, other physicists like Niels Bohr and Erwin Schroedinger made important contributions to the field.

What are the important ideas in quantum theory?

The most important ideas that you should understand in quantum theory are:

  1. Everything in the universe is quantized. Quantities like energy, mass, electric charge and momentum all occur in discrete quantum units. Even space and time occur in discrete quantum units.
  2. The behaviour of particles at the subatomic level cannot be described by classical (Newtonian) physics.
  3. At the subatomic level, particles exist in different quantum configurations called “states”. A State is characterized by its properties, such as energy and angular momentum.
  4. The energy of electromagnetic radiation is transferred in discrete quantum packets known as photons.
  5. According to the Heisenberg Uncertainty Principle, it is not possible to determine the position and momentum of any subatomic particles with infinite precision.

Quantum physics is one of the hardest topics in physics to master. This is the reason many H2, JC and A level students take physics tuition. If you are not confident you will get good grades, then you should consider taking tuition too.