# Inquiry: **Measurement**

## Purpose: To practice measuring using devices of different precision.

## Procedure for metric rulers:

In making measurements with a metric ruler, keep the following suggestions in mind:

- Since the end of the meter stick may be worn, start the measurement at some intermediate mark such as the 1.0 cm mark. Of course, the measurement must be subtracted from the final reading.

- Place the meter stick on edge. This will avoid errors that are easily made when viewing the stick in the flat position.

- In your measurement you should have one sig fig that is ESTIMATED rather than
actually marked on the ruler.

## Procedure for vernier calipers:

Online vernier caliper (measures to 0.1 mm or 0.01 cm)

## Procedure for the micrometer:

Online micrometer (measures to 1 μm) μ is the greek letter "mu" or the prefix "micro" meaning one millionth. 1μm = 0.001 mm

The micrometer below shows by the scale on the
barrel that the measurement is more than 17 mm but less than 17.5 mm. The
horizontal line running down the barrel points about halfway between the 0.20
mm mark and the 0.21 mm mark on the thimble. Therefore, the reading of the
caliper is 17.205 mm. The last digit came from estimating that it was half way(0.5) between the 0.20 mm mark and the 0.21
mm mark on the thimble.

**In conclusion, a meter stick and
the vernier caliper both measure to a tenth of a millimeter with the vernier
being more precise whereas the micrometer measures to a thousandth of a mm
which is a millionth of a meter and thus the term ***micro*meter!

**% Error = |theoretical-experimental| / theoretical**

## Inquiry Questions:

- Pick one of the frog blocks numbered 1-3 and record the number in your notebook.

- Now, determine the length, width and thickness of it using the black & white ruler and record your measurements with the correct precision.

- Now, determine the length, width and thickness of it using the yellow ruler and record your measurements with the correct precision.

- Now, determine the length, width and thickness of it using the vernier caliper and record your measurements with the correct precision.

- Determine the volume, mass and density with the correct sig figs for all three measuring tools.

- Convert your final three densities into mks.

- Determine the diameters of the 16, 18 and 22 gauge wire. Determine the % error using the actual values.

- If you were trying to indirectly measure the thickness of a single page in a 1300 page book and the thickness of the entire book is less than a decimeter but greater than a centimeter, how many sig figs would your answer have if you were using a standard metric ruler? (explain)