What is the difference between an analytical balance and a precision balance?

An analytical balance provides readability of 0.1 mg or better, while a precision balance typically reads to 0.001 g or 0.01 g. Analytical balances include draft shields and are designed for highly sensitive measurements. Precision balances handle larger samples and are less affected by environmental conditions.

What readability do I need for my lab application?

You need a readability that is at least one-tenth of your smallest sample weight or required measurement increment. For example, measuring 100 mg samples may require 0.01 mg readability, while gram-level work may only need 0.01 g. Selecting higher readability than necessary increases cost without improving results.

Do lab balances need to be calibrated?

Yes, all lab balances require regular calibration to maintain accuracy. Calibration ensures measurements remain traceable to certified standards. Internal calibration simplifies this process by automating adjustments, while external calibration requires manual verification with certified weights. In regulated environments, calibration records must be documented and retained.

What is the difference between readability and repeatability?

Readability is the smallest increment of weight a balance will display. Repeatability is the degree of agreement between multiple measurements of the same mass, on the same balance, under the same conditions.

What is the best way to clean my balance to ensure accurate readings?

Inspect and clean before each use. A flannel cloth or soft brush works well for dusting and light cleaning. Use a non-abrasive cleaner for light spills, and a dry flannel cloth for glass parts. Set a regular maintenance schedule for deep cleaning to ensure optimal performance and instrument longevity.

Can vibration affect the accuracy of my balance?

Yes — even slight vibration from a heavy footstep can affect accuracy. Place the balance on a sturdy benchtop away from high-traffic areas such as hallways, elevators, stairways, and doors. If that placement is not possible, an anti-vibration table should be considered.

Tech Challenge: Maintaining Environmental Conditions

Take the challenge and see if you’re right!

Sandy, a graduate student studying insect physiology, is in charge of keeping the walk-in incubator at the correct environmental conditions. The small room is not automated, so she has to monitor the different parameters and make adjustments to the control devices herself when necessary. For her research, she must have continuous, fairly accurate data on the various environmental conditions: 1°C for temperature and 3% or better on %RH. The day/night cycle is easy, because the lights are plugged into on/off timers.

What should Sandy do about the temperature and humidity?

A. Get a thermohygrometer such as the Oakton® Thermohygrometer with Digital Thermometer.

B. Get a temperature and humidity paperless recorder, such as the Extech® Temperature/Humidity Paperless Recorder, and an optional alarm relay.

C. Get a thermometer, such as the Cole-Parmer Thermometer with Time/Date Stamp and Wire Probe, and a psychrometer, such as a Pocket Sling Psychometer.

D. Get a temperature and humidity chart recorder, such as the Temperature/Humidity Strip Chart Recorder.

Click for answers.

Tech Challenge: Maintaining Environmental Conditions

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