Laboratory Scales I

Dr Smith: ‘There are many different types of scales that we use in a biology lab but the most common ones are the top-loading scale and the analytical balance (Dr Smith points to a poster on the wall). Let’s begin with a demonstration of the top-loading balance's basic functions. Any ideas?’

Figure: Types of Balances in a Biology laboratory (Ref. https://biologynotesonline.com/analytical-balance/) 

You: ‘Well I guess we should start by turning on the scale and making sure that it is zeroed.’

Dr Smith: ‘That’s correct! Don’t forget to use the tare button when zeroing your scale to get an accurate reading’.

Watch a video on how to use a common balance: 

Process:

1. Ensure Cleanliness and Stability: Make sure the balance is on a stable, vibration-free surface. Ensure the weighing chamber and pan are clean and dry.

2. Turn On and Calibrate: Turn on the analytical balance and allow it to warm up, if needed. Calibrate the balance according to the manufacturer's instructions to ensure accuracy.

3.Tare the Container:

• Place a clean container or weighing paper on the balance pan. Close the balance doors to prevent air currents from affecting the measurement.

• Press the tare button to zero the balance, setting the displayed weight of the container to zero.

4. Add the Material:

• Open the balance door and carefully add the material to the container or weighing paper. Use a spatula for solid materials to avoid spills.

• Close the balance doors gently to obtain an accurate reading.

5. Record the Weight:

• Once the reading stabilizes, record the displayed weight of the material. Ensure to note the units (e.g., milligrams or grams).

6. Remove and Clean:

• Gently remove the container with the material from the balance. Clean any spillage on the balance with a brush, if necessary.

7. Turn Off the Balance:

• If not using the balance further, turn it off and close the balance doors to protect it from dust and contaminants.

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