Pressure in liquids and gases is primarily influenced by the electromagnetic forces at the microscopic level, particularly through interactions between atoms and molecules. While macroscopic electromagnetic fields are not present, the Van der Waals forces contribute significantly to repulsion and outward pressure when molecules are compressed. However, the discussion highlights that most atoms in a gas or liquid are neutral, suggesting that pressure can exist independently of electromagnetic forces, as evidenced by neutrinos, which exert pressure despite lacking electric charge. The conversation encourages further exploration into systems that exhibit zero pressure. Understanding these dynamics is crucial for grasping the fundamental nature of pressure in different states of matter.
