Science 122Laboratory 
1. Least Count of Measuring Instruments
2. Surface Area of Desk
3. Volume of Wooden Block
4. Timing Downhill Runs
5. Measuring Pendulum Period
1. Define the terms accuracy, measurement, least count, precision, and significant figures.
2. Make proper measurements and record them to the correct number of significant figures using a meter stick and electric timer .
3. Calculate the area and volume when the dimensions of an object are known.
4. Measure the motion of a rolling object and compare it with a calculated value.
4. Determine experimentally and theoretically the period of a simple pendulum.
5. Distinguish between percent error and percent difference.
6. Distinguish between error and precision.
Be sure to describe what type of instruments you are using as part of your lab report. 
Table 1

Numerical Value 
Unit of Measurement 
. 
. 
Table 2

Length 
. . 
Width 
. 
Surface Area 
.cm^{2} 
Volume = length x width x height 

Table 3

Be sure that all measurements are recorded to the correct number of significant figures.
You may find it helpful to place a book or block at the end of the 1 meter run. This will help you to coordinate the timing of the roll.
Table 4.1

Length (L) 
Height (H) 
distance (d) 
.  .  .1 
Time 
1 
2 
3 
4 
5 
6 
Average 
trial 1 
.  .  .  .  .  .  . 
trial 2 
.  .  .  .  .  .  . 
trial 3 
.  .  .  .  .  .  . 
Overall Average time 
sec 
Relationship 4(all units must be consistent, either centimeters or meters) 
for d, L in meters 
for d, L in cm 
calculated (standard) time 
t = 
Percent Error: The accuracy of a measurement refers to how well the experimental value agrees with a standard value. The standard may be a calculated value (as with the can rolling downhill), or a generally accepted value (such as the acceleration of gravity),
Table 4.2

Percent error  . 
Percent Difference: Precision refers to the repeatability of measurements. The closer all of the measurements are to one another, the more precise they are.
Table 4.3

Percent Difference  . 
Relationship 5 

T = period 
Use a small heavy object that has radial symmetry (is not elongated). A cork, a fishing weight, a hex nut, etc. will work just fine. The smaller and heavier the better. Simply tie or otherwise attach a string to it, then tie the string it to a pencil. Lay the pencil on the table so that the pendulum hangs over the edge. Weight down one end of the pencil with a heavy book so that the pendulum bob can swing freely.
Measure the length L from the center of the bob to its support. Make L as close to 49 cm. as you can, but measure the actual length to the appropriate number of significant fgures. 
. 
L = 
cm 
Start the pendulum swinging with a very small displacement. The smaller the arc the more accurate the relationship.
 One swing is one complete cycle, back and forth.
 Let it swing a few times before starting the count.
 Enter the data in the table below.
 Divide the time for ten swings by ten to find the period.
Table 5.1

Trial  Time for ten swings  Period 

1  .  . 
2  .  . 
3  .  . 
4  .  . 
5  .  . 
Average Period = 
sec 
Table 5.2

Period 
sec 
Table 5.3

Percent error  . 
Table 5.4

Percent difference  . 
1. Define "unit" and give an example of it.?
2. Distinguish between least count and significant figures
3. Distinguish between accuracy and precision. See the document entitled "Accuracy vs. Precision" if you need help.?
4. Are your calculations for area and volume rounded to the correct number of significant figures? What should be the appropriate number of decimal places for your 'ruler'?
5. Are any of the time measurements 'really' different from the others? If so, briefly explain why?
6. Why is it preferable to make multiple measurements of time?
7. Use Relationship 5 to calculate the length in centimeters of a simple pendulum that has a period of one second. See the document entitled "Pendulum Length" and substitute a value of 1 sec for T if you can't do the algebra necessary to arrange Relationship 5.
8. Distinguish between percent error and percent difference.
9. What factors might account for the accuracy and precision of the pendulum measurements compared to the ramp?