Name: ______

Title: Triple Beam Balance Lab

Objectives:

• to learn the correct way to use a Triple Beam Balance (TBB)

• to learn the parts of a TBB

• tofind mass by difference and calculate density

Materials:

•Triple Beam Balances

•Various objects (eraser, marker, paperclips)

•Small beaker

•water

Procedure:

PART 1: MEASURING MASS DIRECTLY

1. Check to see that all the Riders are all the way to the left at the Zero mark.

2. Check to see that the Pointer is pointing to zero. If it is not, turn the Adjustment knobslowly until it points to zero. THIS IS CALLED ZEROING THE BALANCE.

3. Place the first object onto the pan. The beams will rise and the pointer will point above zero.

4. Move the rider on thehundreds beam (middle beam) one notch at a time until

The pointer drops and stays below zero. Move the rider back one notch. Record

the number in the hundreds column in Data Table 1.

5. Slide the rider along the tens beam (back beam) one notch at a time until the

pointer drops and stays below zero. Move the rider back one notch. Record the

number in the tens column in Data Table 1.

6. Slide the rider along the ones beam (front beam) until the pointer stops at zero.

Record the number in the ones column in Data Table 1.

7. The Mass of the object is equal to the SUM of the readings on the three beams. Record the mass in the mass column in Data Table 1.

Data Table 1

OBJECT / HUNDREDS / TENS / ONES / MASS (GRAMS)

PART 2: FINDING MASS BY DIFFERENCE/CALCULATING DENSITY

  1. Find the mass of an empty beaker. Record the mass in Data Table 2.
  2. Using the graduated cylinder, add the amount of water as indicated in Data table 2.
  3. Find the mass of the beaker with the water in it and record the number in Data table 2.
  4. Subtract the mass of the beaker and record it in Data Table 2.
  5. Calculate the density (nearest 100th) of water using the formula D= m ÷ v

DATA TABLE 2

WATER
(V) / MASS OF
WATER + BEAKER / MASS OF EMPTY BEAKER / MASS (m) of WATER ONLY / DENSITY OF WATER
D = m ÷ V
(g/cm3)
10 mL
25 mL
35 mL
60 mL
75 mL
90 mL
100 mL

Analysis questions:

  1. Calculate the average density (to the nearest 100th) of water using the data in the last column.
  1. In this lab you calculated the mass of various volumes of water. Calculate the mass of 1 mL of water without using the balance.
  1. Describe how you would find the mass of a certain amount of milk that you poured into a glass.