👉 The term "hemispheres" is a concept in physics and engineering that refers to two interconnected closed surfaces, typically made of metal or plastic, which are used as a means of measuring angles. These surfaces can be arranged into two parallel planes, known as the x-y plane, and one perpendicular plane, commonly designated by the letter z (or sometimes y). The hemispheres provide a convenient way of determining the angle between these two planes. In physics, the hemispheres are often used