Abstract. After doing the practicum of basic physics entitled "Basic measurements and Uncertainty " . The purpose of this practicum are the learners capable to use tools - measuring instruments, determining the uncertainty in the measurement of single and repeated , and understand the use of numbers means . On this practicum conducted three activities , namely length measurement , mass measurement , measurement of time and temperature. the length measurement used three tools that ruler, caliper and micrometer screw. The next mass measurements are also used three kinds , namely ohauss balace 2610 grams , ohauss balance 311 grams , ohauss balance 310 grams . whereas at the time of measurement used a stopwatch and temperature measurement used thermometer. measurement of activities began with determined the value of the smallest scale (SSV) and relative error (RE) of each tool to be used. Then all of object of each was measured three times, it is done to get the exact measurements and more accurate . The object being measured are beam and small ball . Then found the volume and density of the object being measured . Of several measured devices that are used in this experiment , measured instruments which have the highest level of accuracy that is micrometer screw with SSV 0.01 mm
Relative
uncertainty expressed the level of precision of the measurement.
On the experiment,
firstly, we need to read handbook so that we wouldn’t confused in measuring and
collecting measurement date later. After reading the handbook, prepare the
tools and materials needed at the lab. At lab, there are three activities,
namely measurement of length, mass, time and temperature. For length
measurement used ruler, caliper and micrometer screw. While the object are a beam
and small ball. For the mass measurement used ohauss balance 2610 g, ohauss
balance 311 g, ohauss balance 310 g, while the object are beam and small ball.
For time and temperature measurement which used thermometer and stopwatch.
Before starting the measurement activity, we must to determine SSV and absolute
uncertainty (△x)
every tools measurement. Furthermore, measurement did 3 times, that’s done in
order to obtained accuracy of data. Once measured, all the measurement data
along with the absolute uncertainty (△x)
which had to be incorporated into an existing tabel in the guidebook.
Beams are waking up three-dimensional space formed by three pairs of square or rectangular , with at least one pair of which are sized differently . Beams have six sides , 12 ribs and 8 vertex . Beams formed by six congruent square called a cube . The small ball is with curved side is limited by a small curved area .
The small ball is obtained from waking semicircle rotated one full rotation or 360 degrees in diameter.
Length measurement results are data obtained from experiments measuring the length that has been done . length scale is usually expressed in meters(m)
The result is a mass measurement data obtained from the experimental mass measurements that have been done . the amount of mass is usually expressed in grams ( g ) or kilograms ( kg )
First,
prepare the tools and materials to be used in the measurement. Measuring
instrument that is thermometer and stopwatch while the material is a measuring
cup, Bunsen with three legs, the stand, a layer of asbestos. Determine SSV and
absolute uncertainty (△
x) respectively measuring instrument, two, fill water into the measuring cup
250 ml or 1/2 part of the measuring cup and put it on three legs. Third, look
at the temperature early in the thermometer as a reference in later
measurements. Fourth, lit Bunsen and put it under a measuring cup after the
flame is normal. Fifth, while Bunsen put ,the stopwatch is running. Lastly,
every 1 minute people noted that there are temperature changes in the
thermometer up to 6 minutes. Then enter the data presented in Table 5 (the
measurement of time and temperature) with absolute uncertainty (△ x)
Based on three measurement
activities that have been done namely Activity 1 are measure the length ,width,
and height of beam and diameter of small ball by using a ruler, caliper, and
micrometer screw. Where the ruler has the SSV value Δx = 1 mm and 0.5 mm,
calipers have SSV Δx = 0.05 mm and 0.05 mm, and a micrometer screw has SSV Δx =
0.01 mm and 0.005 mm. measurement of every things have been done three times,
it is aimed to obtain accuracy data but may be due to the influence of the
outside that makes the measurement result obtained differently by each person
and also usually the fault of observed everyone not just in tools measured. Because
of the repetition of data collection is done up to 3 times so as to measure X need
to be repeated measurement to obtain the true value more accurately. In the
second activity is done took beam mass and small ball used Ohauss balance,
where the Ohauss Balance there are 3 kinds, namely: Ohauss Balance SSV 2610
grams with 0.1 grams / scale, Ohauss Balance SSV 311 grams with 0.01 gram /
scale and Ohauss Balance SSV 310 grams with 0.01 gram / scale. And on the third
activity was measured using a temperature measuring instrument with SSV
thermometer 1 ̊C / scale and time using a stopwatch measuring instrument with a
0.1 second SSV / scale.
1. I was able to use the basic measuring tools . such as length measuring devices , mass measuring devices , and measuring the temperature and time . From these observations I conclude that the smaller scale measuring instruments used the smaller the degree of guilt . The smaller the uncertainty the relative , the higher the accuracy achieved in the measurements.
2. I capable determine uncertainty single and repeatedly. Uncertainty in a single measurement using
so that the results of a single measurement bit dubious because only use allegations . whereas ,uncertainty in measurement repeatedly
, where △x is deviation (the difference between each of the measurement results of the average value).
From these data we can conclude the uncertainty in measurement single higher than a single measurement.
3. I was able to understand the number mean. The number mean can be concluded depending on the accuracy of measuring instruments . The more rigorous measurement tool is used , the more important figure . However, an number mean in the measurement has certain limitations are (1)all non-zero numbers are number mean. Example : 72.753 ( 5 number mean). (2) All zeros are located between nonzero numbers are number mean. Example : 9000.1009 ( 9 number mean).(3)All zeros are located behind the last non-zero digit , but it is located in front of the decimal sign is number mean. Example : 3.0000 ( 5 number mean) .(4)Zeros are located behind the last non-zero digit , and behind the decimal point are number mean. Example : 67.50000 ( 7 significant digits ) .(5)Zeros are located behind the last non-zero digit and the decimal point is not important figure . Example : 4700000 ( 2 number mean).(6)Zeros are located in front of the first non-zero digit is the number is not important . Examples : 0.0000789 ( 3 number mean)
SUGGESTION
Once we got the basic measurement of these differences or uncertainty in each measurement. When conducting experiments on beam cube and the ball turns in the measurement uncertainty in each measurement is indeed the case, for example, measurements of length, width, height, ball diameter, mass, temperature and time. Of each measurement was proved to have different results, although the difference is not too far away. This is caused by the factors of uncertainty. For example, errors in the calibration, which is caused by a lack of good tools, it could be because of an error reading scale, or because of limited precision gauges and other uncertainty factors.
