Deionizer with 4 elga cans

The best definition of a balance lever is a simple machine that consists of a rigid bar or beam that pivots around a fixed point called the fulcrum. It is used to compare the weights or forces of two objects and determine if they are in equilibrium (balanced) or if one side is heavier than the other (unbalanced). The balance lever operates on the principle of torque, where the torque (rotational force) exerted on one side of the fulcrum is equal to the torque on the other side when the system is in equilibrium. This principle is expressed by the formula: Torque = Force × Distance from fulcrum. By placing known masses or weights on one side of the lever and an unknown weight on the other side, the balance lever can be used as a weighing scale. When the lever is in balance, the two sides are equal in weight or force. This concept has been widely used in various applications, from traditional weighing scales to more complex systems like seesaws or construction equipment.

The Barlow's wheel apparatus is an experimental device used to demonstrate the conversion of electrical energy into mechanical energy through electromagnetic principles. It consists of a horizontal wheel or disk with radial metal spokes attached to its center. The wheel is mounted on an axle, allowing it to rotate freely.

A "bell in vacuum" apparatus is a scientific setup used to demonstrate the effects of reduced air pressure (vacuum) on sound transmission. It typically consists of a bell or sound-producing object enclosed within a sealed chamber from which air has been removed, creating a low-pressure environment. This apparatus is designed to illustrate how sound travels differently in a vacuum compared to in normal atmospheric conditions, highlighting the role of air molecules in sound propagation.