Anaesthesia physics focuses on the principles and equipment that ensure safe delivery of anaesthesia, including the anaesthesia machine, which precisely delivers a controlled mixture of gases and vapours; breathing circuits, which connect the patient to the machine and regulate inhalation and exhalation while maintaining optimal gas composition; and vapourisers, which convert liquid anaesthetic agents into a measured vapour form for accurate mixing with carrier gases, enabling consistent and safe anaesthetic depth throughout a procedure.