Lab #1: Discussion, Error and Precaution, Conclusion

Discussion

The lengths of a glass prism, stool, beaker, copper wire and metal pin were made using 3 measuring

instruments. The accuracy of the instruments (how close the readings are to the 'true' value) could not

be determined as no true values of the quantities being measured were given. The instruments with the

greatest precision (intention to make observations with the greatest possible x aptitude) were the

vernier calipers because they were able to measure quantities to two significant figures. The meter rule

had the least precision as it only made measurements to one significant figure. The micrometer screw

gauge was the most sensitive (had the largest response to unit change in input) as its s cale would

experience the most graduations for a fixed length amongst the 3 instruments. Finally the meter rule

had the greatest range (interval between minimum and maximum values able to be measured) being

100cm but was also the least sensitive instrument.

It was necessary to take repeated readings of the measured quantities in order to eliminate uncertainty

or random error. However, parallax error was hard to avoid when measuring the stool as the point on

the scale was way higher than my line of sight. As seen in all except one of the readings, the

consistencies in the measurements show that these readings were very precise.

In measuring the thickness of the beaker, the difference between the external and internal diameters

was needed to be divided by 2 so that the final result would not represent the thickness of two sides,

but one only.

The results obtained were as expected with the stool, the largest object having the greatest overall

measurement with the strand of copper wire having the least.

Sources of Error

Parallax Error: a parallax error was experienced when taking the length of the stool because of

the stool’s elevated position and the point on the scale being above my line of sight. However, it

was soon realized and corrected.

There was a bit of uncertainty in reading the micrometer screw gauge when measuring the

width of the strand of copper wire.

Precautions

To avoid parallax error, I made sure that all my readings were made at eye level, with one eye

which was used for throughout.

To avoid uncertainty, repeated readings of the quantities were recorded.

Conclusion

The lengths of the instruments that were to be measured were recorded successfully.