Mechanical Balance

Bar and gauge apparatus is used to demonstrate thermal expansion and cooling contraction in classrooms and laboratories.

A barometer tube is a slender, sealed, and typically transparent tube used in barometers to measure atmospheric pressure. It is usually filled with a liquid, often mercury, but sometimes water or another fluid, which rises or falls within the tube in response to changes in atmospheric pressure. The height of the liquid column in the tube serves as an indicator of the current atmospheric pressure, with higher pressure causing the liquid to fall and lower pressure causing it to rise. This measurement helps in predicting weather changes and understanding atmospheric conditions.

The best definition of a bell jar apparatus is a scientific instrument used in laboratories to create a controlled environment for various experimental purposes, such as studying the behavior of gases, conducting vacuum experiments, or demonstrating principles of physics and chemistry. It consists of a glass or transparent plastic container shaped like a bell, which can be sealed to create a vacuum chamber. The apparatus allows researchers to manipulate and observe the interactions of substances or objects within the vacuum or controlled atmosphere, often enabling investigations that wouldn't be possible under standard atmospheric conditions.