How to Use a Triple Balance Beam

by: Amy Nicholas

A Triple Balance Beam is the way a lab will measure the amount of mass in grams of an object. Measuring of mass will be in the range of tenths of a gram through tens of grams. The name of the triple balance beam is in reference to the three beams that are used to calculate the overall mass of an object on the triple balance beam scale.

Things that you will need to measure an object on a balance beam are:

• triple balance beam
• measuring object
• placemat
• calculator

Before weighing an object, set the balance beam on a plastic mat to avoid scratching of a table or balance beam. When starting to measure the object first "zero" the scale. Do do this by sliding back all the weights until all three pointers are at zero. In the photo below it shows what a balance beam should look like when set to zero.

Once the balance has been calibrated, place the object to be measured on the scale. You should notice that the pointer on the scale immediately moves, and the scale is no longer zeroed. Move the 100-gram slider along the beam to the right until the balance pointer rises above the zero mark. Where the 100-gram slider is placed when the pointer rises above zero is the amount that will be measured in 100-grams. In the photo below the 100-gram mark is placed at 100.0 grams which means the amount that will be measured is 100.0 grams.

Move the 10-gram slider along the beam to the right until the pointer moves slightly above  the fixed mark. Where the 10-gram slider is placed when the pointer is slightly above the mark is the amount measured in 10-grams. In the photo below the 10-gram mark is resting at 40.0 grams which means the amount that will be measured is 40.0 grams. 

Move the 1-gram slider along the beam to the right until the pointer moves exactly to the fixed mark on the scale. Where the 1-gram slider is placed when the pointer is exactly on the fixed mark is the amount measured in 1-grams. In the photo below the 1-gram mark is resting at 2.5 grams which  means the amount that will be measured is 2.5 grams.

When calculating the overall mass of an object simply add up the calculated amount from the 100-gram, 10-gram, and 1-gram sliders on a calculator to figure the overall mass of the chosen object in grams. The amount measured above would be calculated by adding all totals together to equal the overall mass amount of the measuring object. In the photo below all sliders are properly calculated to figure the correct mass in grams of the measuring object. 

Correctly calculating the mass is very easy to complete. Always remember to add all three sliders together to find the total mass amount and the answer will always be correct. Failure to add all three sliders together will cause the answer to be incorrect and the data will be wrong.