The fundamental difference between a beam balance and a measuring cylinder lies in the physical quantity they are designed to measure: a beam balance measures mass, while a measuring cylinder measures volume.
Here's a detailed comparison:
| Feature | Beam Balance | Measuring Cylinder |
|---|---|---|
| Primary Measurement | Mass | Volume |
| Physical Quantity | Amount of matter in an object (measured in grams, kilograms) | Amount of space occupied by a substance (measured in milliliters, liters) |
| Association with Liquid | Non-mandatory for the beam balance | Mandatory; primarily used for measuring liquid volumes |
| Principle of Operation | Compares an unknown mass to known standard masses | Relies on calibrated markings to indicate volume |
| Typical Use | Weighing solids, liquids (in containers), or gases | Measuring the volume of liquids or irregular solids (by water displacement) |
| Units | Grams (g), Kilograms (kg) | Milliliters (mL), Liters (L), Cubic Centimeters (cm³) |
Understanding the Distinct Functions
As per the reference, "measuring cylinder, graduated beaker, overflow can are used to measure the volume and the liquid is (mandatory) associated with each of these measuring instruments. But, the beam balance is used to measure the mass of a substance and the association with liquid is non-mandatory for the beam balance." This clearly outlines their primary purposes and material associations.
Beam Balance: Measuring Mass
A beam balance, often referred to as a "double-pan balance" in its classic form, operates on the principle of comparing an unknown mass with known standard masses. It is a highly precise instrument used in laboratories, jewelry shops, and various industries to determine the mass of an object. When using a beam balance, you place the substance (whether it's a solid, or a liquid contained in a beaker/flask) on one pan and known weights on the other until the beam is balanced. The reading from the known weights then indicates the mass of the substance. Its application isn't restricted to liquids; it can measure the mass of any substance.
- Practical Example: Determining the exact mass of a chemical compound needed for a reaction, or weighing a sample of ore.
Measuring Cylinder: Measuring Volume
Conversely, a measuring cylinder is a tall, cylindrical glass or plastic vessel with a flat base and a spout for pouring. It has calibrated markings along its side to indicate specific volumes. These cylinders are specifically designed to measure the volume of liquids accurately. When measuring, the liquid is poured into the cylinder, and the volume is read at the bottom of the meniscus (the curved surface of the liquid). While primarily used for liquids, they can also be used to find the volume of irregular solids through the water displacement method.
- Practical Example: Measuring 50 mL of water for a solution, or determining the volume of an irregularly shaped rock by submerging it in water and observing the volume change.
In essence, a beam balance tells you "how much stuff" is there (mass), while a measuring cylinder tells you "how much space it takes up" (volume).
