Behoudswetten

Behoudswetten, also known as conservation laws, are fundamental principles in physics stating that certain physical properties of an isolated physical system do not change over time. These properties are called conserved quantities. The most well-known examples include conservation of energy, conservation of momentum, and conservation of angular momentum. Conservation of mass was a separate law in classical physics but is now understood as part of the conservation of energy and mass-energy in relativistic contexts.

These laws are crucial because they simplify the analysis of complex systems. Instead of tracking every individual particle's behavior, physicists can focus on how conserved quantities are transferred or transformed. For instance, in collisions, the total momentum before and after the collision remains the same, even if the individual momenta of the colliding objects change.

The concept of conservation laws is deeply connected to symmetry through Noether's theorem. This theorem states that for every continuous symmetry of a physical system, there is a corresponding conserved quantity. For example, the conservation of energy is linked to the symmetry of physical laws under time translation, meaning the laws are the same today as they were yesterday. Similarly, the conservation of momentum is related to the symmetry of physical laws under spatial translation, meaning the laws are the same everywhere. Conservation of angular momentum is associated with rotational symmetry.

Behoudswetten are not only descriptive but also predictive, guiding the development of theories and the interpretation of experimental results across all branches of physics, from classical mechanics to quantum field theory.