Lab weighing: Small habits that make a big difference

Weighing substances in the lab is a process that requires precision and consistency.  To keep your workflow steadily progressing, and your results accurate, here’s some habits that make this tricky task a little easier. 

• Manage your environment

While you're climatised to your lab environment, your balance may not be. If your results are constantly struggling to stabilise for no apparent reason, the environment you’re in might be the problem.  Check the temperature When you’re measuring substances on a semi-micro level, sudden temperature shifts can lead to inconsistent readings. Changing temperatures can: 

• Make the metals and plastics in the scale expand and contract at different rates, altering the inner mechanisms. 
• Create convection currents within the draft shield. This causes the weighing pan to rise and puts pressure on the samples. 

Keep your scale at a consistent temperature throughout the day. Do this by storing it away from the sun, warm machinery, vents and windows.  If you have to move the scale, make sure you leave enough time for it to re-adjust to the new space’s temperature before use.  

Decrease humidity

High humidity can generate static electricity. This interferes with your scales when trying to record precise results.  Your scales work best when the humidity of your work area is below 40%, so consider using a HVAC system or dehumidifier to keep the humidity low.

Limit vibrations

In busy labs, vibrations are constant, so they’re difficult to completely avoid. But, using anti vibration tables and supports to put your scales on can help. This helps to keep your measures and recordings more accurate. 

• Prepare your scales 

Use the right balance  Measuring quantities with a scale is made much easier when you’re using the right equipment. Different weighing scales are specialised for different applications, so make sure you choose one that’s made for the job. Consider:  

• What is the scale's maximum capacity? 
• How readable is the scale?
• What kind of applications are you using the scale for? 

Make sure the balance is level

Your balance needs to be level to be able to record measurements accurately. Using a levelling bubble guarantees this.  Adjusting the front and back feet, you can make sure the bubble is centred which makes it easier for you to record accurate results.  When your scales aren’t level, the weight of your samples aren’t distributed evenly.  Cleaning regularly  Residue left on your scale after use can build up over time and affect your measurements. This could be dust, spilt powder, liquid residue and oils from handling. To avoid this being an issue, clean regularly and thoroughly. Do this using a microfibre towel and an ethanol-based cleanser. 

• Regulate samples

Use room temperature samples When possible, weigh samples that are the same temperature as the scales you’re using. Ideally, this should be room temperature. To allow the sample and scale to equalise, place them next to each other. 

Powders without static Powder samples can develop static. Because the particles are constantly creating friction between themselves, it’s difficult to prevent staticky powders. Use an ioniser to neutralise any static in the sample. 

• Re-think your technique

Wear gloves

Avoid touching anything with your bare hands when using lab scales. Oil and sweat on your fingers spreads, and this can affect measurements when conducting hyper-specific research. Instead, use gloves or tweezers. 

Don’t forget to tare Tare is a function on your scales that allows you to weigh samples without the weight of the container holding the substance. Make sure you’re doing this before recording any measurements, and make it a habit to reset the results on your scale before the end of the day. 

Refer to the manual

Every weighing machine scale is different. It’s important to read the manual, and refer to it if you’re struggling to get your readings to stabilise and stay consistent. Keep the manual nearby when working with scales and familiarise yourself with the available functions. 

Take your time Don’t rush! Make sure you’re completing all the necessary steps and waiting for the results to fully stabilise. Laboratory balances are famously sensitive so they take a little longer to stabilise. Take time to do things properly to avoid making mistakes. 

Final thoughts 

There are a lot of variables at play when trying to weigh precise measurements. This makes weighing substances in a lab a difficult, and sometimes tedious task. But by working these habits into your process you’re giving yourself the best chance at consistent, accurate results.