Measuring Mass

1
Measuring Mass

• Using a Triple Beam Balance

2
To Find the Mass of an Object

• Make sure the balance is on a level surface and
  that nothing is on the balance pan.
• Bring all three sliding masses (riders) to the
  zero point at the left of the beam. Make sure
  the two larger masses are placed in the notches
  at the beginning of the beam

3
To Find the Mass of an Object Contd

• If the pointer does not line up with the zero
  mark, adjust the fine-adjustment screw, which is
  under the balance pan.
• Put the object you want to measure in the center
  of the balance pan.

4
To Find the Mass of an Object Contd

• Move the large sliding mass along the beam notch
  by notch until it is just too heavy (making the
  balance beam drop below the zero mark at the
  end). Then put it one notch back to the left.
  Make sure the mass fits properly into the notch.
• Repeat step 5 with the middle sliding mass.

5
To Find the Mass of an Object Contd

• Carefully slide the smallest mass until the
  pointer is centered on the mark. Use a pencil to
  make movements more gradual.
• The mass of the object is the sum of the readings
  shown by the positions of the three sliding
  masses.

6
Things to Remember

• Always use two hands to carry a balance one
  hand on the knife the other on the center post.
• Do not overload your balance!
• Keep your balance clean and dry.
• Do not place chemicals directly on the balance.
  Use a suitable container such as a watch glass
  or beaker.
• Never place a hot object on the balance
• If your balance does not work as expected, ask
  your teacher for help.

7
Using an Electronic or Digital Balance

• Turn on the balance and wait until the display
  reads zero.
• Place the object in the center, and read the
  number of grams directly.
• To find the mass of a substance in a container
• Turn on the balance and wait until the display
  reads zero.
• Place the empty container at the center of the
  electronic balance pan. Press tare or
  rezero. The display will now read 0 g again.
• Remove the container, fill it with substance to
  be measured, and put it back on the center of the
  balance pan. The display will then register the
  mass of the substance (without the mass of the
  container).