1. Precision of Measurements

2. Goals:
1. Know what measurement tool is used to take different measurements.
2. Understand that the precision of a measurement is determined by the instrument used.

3. Volume Measurements Volume is the amount of space an object occupies.
To determine volume of a regularly shaped object, we use a metric ruler (length x width x height).
To determine the volume of an irregularly shaped object, we use the displacement method.

4. Reading a Graduated Cylinder

5. Reading a Graduated Cylinder
Always measure from the bottom of the meniscus
You must record 1 digit more than the interval of the instrument
MENISCUS

6. Determining the Interval
Example: Look at the sample graduated cylinder.
The interval is the value of each of the lines.
In this case, the interval is “1”.
Our measurement needs to go to one digit past the
“ones” place. Therefore, in this example, our
Measurement would need to go to the tenths place.

7. Example: Graduated Cylinder
The interval is 1 mL
Our measurement needs to be to the tenths place
So a proper measurement might be 73.0 mL

8. Length Measurements Interval is 0.1 cm
So our measurement needs to go out to the hundredths place!

9. Determining the Intervals
Take a look at the measurement tools at your station. Determine the interval of the following:
10 mL graduated cylinder: _______
Thermometer: _________
Triple beam balance: _________

10. Have Ms. V check your intervals BEFORE you proceed with taking measurements!