Which apparatus is used to measure mass

Laboratory balances, considered general lab equipment , are essential measuring instruments because they can deal with such small measurement units. The balance compares an object with a known mass to the object in question. Different types of balances include digital scientific balances and beam balances, such as a triple beam balance. The standard unit of measure for mass comes from the metric system and is either grams or kilograms.

At home, you typically use a modern digital or spring scale to determine mass. A person can stand on the common bathroom scale to obtain their body weight. A lab balance, also known as an analytical balance, is designed to measure small mass in the sub milligram range. Scales measure mass directly by counteracting the downward force by another equal downward force on the opposite side.

On a beam balance with two pans, you have enough mass on the opposite pan to counterbalance the unknown mass with no force measured. This instrument compensates for differences in the acceleration of gravity at different locations on Earth. While the most common type of instruments used to measure mass is the beam, there are also load cell instruments to measure mass. These are more sophisticated weighing machines that are highly accurate.

The strain gauge load cells have a typical accuracy of one part in 2, Frequency shift technology instruments have even better accuracy using ceramic capacitive strain gauges, which can be made with accuracy up to one part in 30, One drawback to this type of measuring is the scale can be broken.

Newer scales use technology that incorporates spring shock dampers to minimize this issue. Force restoration instruments apply force restoration technology to weigh measurement. More common bench scales range up to 25 lbs, with the accuracy approaching one part in 1 million. The maximum load rating of commercial instruments reaches up to 13, lbs. There are, however, special devices that have much larger capacities.

In situations where mass cannot be determined by using a balance, such as measuring the mass of a liquid in a tank, transducers are used. The unit of time is second, which is symbolized by s. For longer intervals of time the minute min and the hour hr are used, but the worldly accepted unit is seconds s so with any calculation, the longer intervals of time is converted to seconds s.

Powered by GitBook. Instruments of Measurement. Instruments of Measurement Devices that are used in taking measurements are referred to as instruments of measurement. Measuring the mass of objects The mass of an object is measured with a balance.

We have different types of balances; some examples are; Top pan balance or compression balance Beam balance Electronic balance Lever balance Instruments for measuring length We use different types of instruments depending on the object you want to measure because all the instruments play different roles.

The positions on the beam at which the weights rest indicate the mass of the object. To calculate a mass, a spring is displaced by the downward force which then causes a load cell to send an electrical current to a signal processor, which then displays the mass. By using this method, these balances can precisely determine the mass of a substance. Analytical balances are very precise instruments and most measure down to ten thousandths of a gram, while some can even measure down a hundred thousandth of a gram.

An analytical balance contains several key components. The weighing pan is where samples are placed. It is the component of the scale that is linked to either the balance beam or spring. The air or draft shield, the glass enclosure with movable doors atop the balance, prevents air currents and dust from coming into contact with the weighing pan, and in turn causing the measurement to be inaccurate.

The tare bar is used to re-zero the scale after the weigh boat or weigh paper is placed onto the weighing pan. Weigh boats and weigh paper are used to hold substances for measurement on the balance. They prevent the weighing pan from getting dirty or damaged by chemical reagents. Spatulas are the instruments used to manipulate the samples that are to be weighed. Depending on the type of substance and how much needs to be weighed, a microspatula can be used for smaller quantities. The scoopula is used to mass larger quantities.

To use an analytical balance, make sure the scale is on by pressing the tare bar. Open the draft shield door and place the weigh boat or weigh paper on the scale. Close the draft shield. Press the tare bar again and the scale should now read 0. The amount of substance that needs to be weighed also determines whether a weigh boat or weigh paper is used. For smaller amounts, or if the substance is going into a tube such as a small vial or microfuge tube, weigh paper is utilized.

Weigh paper is often folded for easy handling. Weigh the substance onto the weigh pan without spilling onto it using a spatula. While weighing, allow the reading to stabilize. If necessary, close the door of the draft shield to ensure an accurate reading. Also, be sure not to lean on the bench while using the analytical balance as this could affect the reading.

After weighing, be sure to clean off any debris that may have spilled onto the pan using a brush. Remember to always wear gloves when working with an analytical balance.

Wearing gloves prevents fingerprints from getting on the weighing pan. When it comes to massing, hygroscopic substances, which are substances that take up moisture, do it quickly, since they will absorb moisture during weighing. Always allow frozen or refrigerated substances to come to room temperature, in order to prevent the chemical from absorbing moisture. A cold chemical will be heavier than one warmed-up, and cause your measurement to be incorrect. Also always make sure the balance is level, by locating the leveling bubble and verifying that it is centered.

If not, the balance may have adjustable legs that can be turned to allow the balance to be level on an uneven surface. Moreover, balances are often located on a vibration-absorbing block, which protects the electronics from vibration. To periodically, check that your balance is giving good readings, analytical balances often come with calibration weights. These standard weights have precise, specific mass, and allow a way to check the accuracy of the balance.