bare enamelled copper wire

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 Bernoulli tube apparatus, also known as a Venturi tube apparatus, is a scientific device used to demonstrate the principles of fluid dynamics, particularly the Bernoulli's principle. It consists of a specially shaped tube with a constricted region, often referred to as a Venturi section. When fluid (liquid or gas) flows through the tube, the constricted section leads to changes in pressure and velocity according to Bernoulli's principle, which states that as the velocity of a fluid increases, its pressure decreases and vice versa. This apparatus is commonly used in educational settings to visually illustrate how the flow of a fluid can affect its pressure, helping to explain various phenomena like lift in aircraft wings, fluid flow through pipes, and more.