Measuring
Mass
using the
Metric System
Alice L. Comisky
MASS
Definition: Mass is the amount of matter in an
object.
Tools: triple beam balance
Unit of measure:
gram-used in science class
The most common tool used in science class for measuring
mass in the metric system is the triple beam balance. The
mass of an object can be found to the nearest tenth of a
gram using this tool.
Take the time to learn the names for the parts
of the triple beam balance.
Pan
Adjustment Knob
Pointer
Upright
Base
Zero
The back or 100-gram, beam is divided into ten units of 10
grams each.
The middle, or 500-gram, beam is divided into five units of
100 grams each.
The front, or 10 gram, beam is divided into ten major units
of 1 gram each. Each of these units is further divided into
units of 0.1 gram.
Zero the balance
Before using the triple beam balance make sure all
three riders read zero and the pointer is at zero.
If the pointer is not at zero turn the adjustment
screw under the pan until the pointer is at zero.
Helpful Hint: On most balances turning the knob
towards you will move the pointer down. Turning
the knob away from you will move the pointer up.
When the pointer
is at zero your
balance is ready
to use.
What steps must
you take if your
pointer is not at
zero?
Turn the adjustment screw
under the pan until you bring
the pointer to zero.
Following the steps on the next 9
pages you will learn how to use the
triple beam balance to find the mass
of a solid, a powder and a liquid.
**Finding the Mass of a Solid**
1. Zero the balance
2. Place the object on the pan
3. Move the rider on the middle beam notch by notch
until the pointer drops below zero. Move the rider
Back one notch.
4. Move the rider on the back beam notch by notch
until the pointer again drop below zero. Move the
rider BACK one notch.
5. Slowly move the rider along the front beam until
the pointer stops at the zero mark.
6. The mass of the object is equal to the sum of the
readings on all three riders.
What mass is shown by the riders on this triple beam balance?
455.7 g
What mass is shown by the riders on this triple beam balance?
322.0 g
Finding the Mass of a Powder
1. Zero the balance
2. Place a mass boat (or a sheet of filter paper) on the pan.
Find the mass of the mass boat. Record the mass.
filter paper
weighing pan
the mass of this mass boat is 1.9 g
Finding the Mass of a Powder
3. Place the powder in the mass boat. NEVER place the
powder directly on the pan.
4. Find the mass of the mass boat and powder.
Finding the Mass of a Powder
5. Record the mass of the mass boat and powder.
6. Subtract the mass of the mass boat from the combined mass of
the mass boat and powder. The result is the mass of the powder.
The combined
mass of the
mass boat and
the powder is
103.4 g.
103.4g combined mass
- 1.9g mass of mass boat
101.5 g mass of the powder
**Finding the Mass of a Liquid**
1. Zero the balance
2. Place a beaker on the balance pan. Find the mass of the
beaker. Record the mass.
The mass of the beaker is 51.1g
Finding the Mass of a Liquid
3. Pour the liquid into the beaker and find the combined
mass of the liquid and the beaker.
The combined
mass is 93.2g.
Finding the Mass of a Liquid
4. Subtract the mass of the beaker from the
combined mass of the beaker and liquid. The
result is the mass of the liquid.
93.2 g combined mass of beaker and liquid
51.1 g mass of the beaker
42.1 g mass of the liquid
Review this
presentation and
take the time to
practice using the
triple beam
balance.
Alice L. Comisky