How do you read a triple beam balance?
This site seems to explain it very well.
http://www.wisc-online.com/objects/index_tj.asp?objID=GCH202
To read a triple beam balance, follow these steps:
1. Set up the triple beam balance on a flat and stable surface.
2. Before placing any objects on the balance, ensure that all three beams (the largest, middle, and smallest) are set to zero by adjusting the corresponding riders or sliders to the leftmost positions. If any of the beams are not at zero, adjust them accordingly.
3. Carefully place the object you want to measure on the center pan of the triple beam balance.
4. Start with the largest beam (the one with the largest increments). Move the rider or slider on this beam to the nearest notch position below the object's mass, making sure the balance is level. For example, if the mass of the object is 115 grams, set the largest beam to 100 grams (if available) or the closest notch below it.
5. Next, move to the middle-sized beam and adjust its rider or slider until the balance is level again. Note the mass reading at this point. Each notch on this beam represents 10 grams, so if the rider is on the 3rd notch, the reading will be 30 grams.
6. Finally, move to the smallest beam and adjust its rider or slider until the balance is level. Note the mass reading for this beam. Each notch on this beam represents 0.1 grams, so if the rider is on the 5th notch, the reading will be 0.5 grams.
7. To calculate the total mass of the object, add up the mass readings from each beam. For example, if the largest beam reads 100 grams, the middle-sized beam reads 30 grams, and the smallest beam reads 0.5 grams, then the total mass of the object is 130.5 grams.
It's crucial to remember that you should always handle a triple beam balance with care and avoid touching the beams or riders while making measurements.