What is the difference between the instruments for measuring mass and weight

What springs to mind when many people think of a balance is a traditional model, such as a two-pan balance.

The weighable material is placed in one pan, and calibrated metal weights in the other. Other types of traditional balances include:. However, in a modern laboratory setting, you are likely more used to using precision and analytical balances like the ones in the image below. The force of the sample is lifted by an electromagnet and the current required to oppose the weight is measured. Definitions for the different types of lab balances may vary but here are general guidelines for what constitutes a precision balance and an analytical balance:.

Other types available include semi-micro, micro, and ultra-micro balances. According to Sartorius , these are capable of reading the following units:. Bear in mind that all of these types of balances may be referred to as scales in some literature, even that coming from manufacturers. For example, Torbal has a Laboratory Balances category , but refers to all of its balances as scales. In addition, Mettler-Toledo, a worldwide industry leader in weighing solutions, has product literature for one of its analytical balances that refers to the product as a balance, a scale, and a balance scale.

As mentioned, scales are often used to weigh larger masses, such as raw materials, reagents, and products in a production setting. However, they may be used in commercial or household settings to weigh smaller masses, such as produce in a grocery store, or ingredients for baking. There are two main categories of scales: mechanical and digital.

Within these categories, there are a plethora of different types of scales, including bench scales, home weighing scales, kitchen scales, and so on. Below are just a few of the scales you might see in use:.

A home weighing scale, an Ohaus Checkweigher , and a kitchen scale. To add to the confusion, compact or portable balances are very often referred to as scales. Standard reference masses are 5g, 10g, 20g, 50g, g, g, g, 1kg, 2kg, 5kg. This type of balance is commonly used in provision and grocery shops Figure The pans rest on top of the beam and can be conveniently placed on a table top.

This balance is used in labs and is similar to the beam balance but it is a lot more sensitive and can measure mass of an object correct to a milligram Figure The standard reference masses used in this physical balance are 10 mg, 20 mg, 50 mg, mg, mg, mg, 1 g, 2g, 5 g, 10 g, 20 g, 50 g, g, and g.

Nowadays for accurate measurements digital balances are used, which measures mass accurately even up to a few milligrams, the least value being 10 mg Figure This balance helps us to find the weight of an object. It consists of a spring fixed at one end and a hook attached to a rod at the other end. A pointer is attached to the rod which slides over a graduated scale on the right.

The spring extends according to the weight attached to the hook and the pointer reads the weight of the object on the scale. Solve — The mass of 40 apples in a box is 10 kg. Mass m is the quantity of matter contained in a body.

Weight w is the normal force N exerted by the surface on the body to balance against gravitational pull on the object. In the case of spring scale the tension in the spring balances the gravitational pull on the object. The transducer works by sending a signal to a processor, which then makes the mass calculations.

An indicator then displays the mass. Taking the measured mass of the liquid below the transducer and subtracting the mass of the vapor, the mass of a floating roof, and the mass of the bottom sediment and water yields the gross mass. Dealing with measurements of physical properties on the microscopic level presents several challenges. One of the most effective methods for measuring fluid is to use the vibrating tube mass sensor.

After this has been found, absolute mass can be determined by measuring the buoyant mass of the object in fluids of different densities. This is an ideal, affordable, and portable solution to measure biomaterials such as seeds, cells, and embryos. Interested in leasing scientific lab equipment? We can help. There is a common misconception that mass and weight are the same things, which can lead to an incorrect choice of which instruments should be used to measure mass.

The reason why weight and mass are used interchangeably is because they are proportional to one another. However, the mass of an object represents the amount of matter within it, while weight depends on the force acting on the object due to gravity. Measuring mass does not always measure weight. Mass will not change regardless of where an object is located because the amount of matter remains the same. If the object is interacting with Earth, the force is known as the weight.

The unit for weight is the Newton but it can also be expressed in pounds or kilograms. Ensure the balance is on a level surface, and do not place the sample directly on the balance. Because some chemicals in a lab could damage the surface of the weighing pan, you should use a weighted boat, weighing sheet, or some other container such as a graduated cylinder, to hold your sample.

If your balance has doors, close them before taking measurements because the air movement will affect the accuracy of the mass measurement. If there are no doors, make sure the area is free of vibrations and drafts. When you place your sample in a container, you end up with the combined mass of the container and your sample.