Name
Laboratory Section
Physics 1020
Laboratory 1: Measurement
Prelab sheet (page 1 only)
1. Laboratory 0. Read the Laboratory Guide for Physics 1020 (available on the web
through the Physics 1020 Homepage).
2. Measure the length of your foot in centimeters 10 times and record your
measurements in the table below.
1
2
3
4
5
6
7
8
9
10
a) What is your best value for the length of your foot? How did you determine
it?
b) What is the uncertainty in your best value? How did you determine it?
1
Name
Laboratory Section
Laboratory 1. Measurement:
How to Determine Human Reaction Time Without a Stopwatch.
Last semester when you studied the motion of falling bodies with constant acceleration g
you found that
d = ½ gt2, where d is the distance fallen, g is the acceleration due to gravity at
the surface of the Earth = 9.8 m/s2, and t is the time of fall. In this experiment we will use this
formula to determine human reaction time.
Procedure: One student in each experimental group should hold the meter stick so that another
student can place their thumb and index finger on either side of the bottom of the meter stick.
The first student will drop the meter stick without informing the second student when it is being
dropped. The second student will catch the meter stick with their thumb and index finger.
Measure the distance the meter stick has fallen 5 times, and record it in the table below.
Distance fallen
1
2
3
4
5
Using these measurements we can determine the reaction time.
If d = ½ gt2 then
t2 = 2d/g and
t = √ 2d/g
2
Name
Laboratory Section
Using the measurements you have made above calculate the reaction time for each
measurement.
Reaction time
1
2
3
4
5
Determine the best value and the uncertainty for the reaction time.
Reaction time (best value) =
Uncertainty =
Repeat this process and record the reaction times for each student in the group. (You will
need to make (neat) copies of the 2 data tables above on separate paper and attach them to
your final lab report. Compile the results for all the students in the group in the table
below.
Student
Reaction Time (Include Uncertainty)
1
2
3
4
5
3
Name
Laboratory Section
Given the evidence you have acquired what can you say about the hypothesis “All students in
the experimental group have the same reaction time.” Give the reasons for your answer
Bar trick: A crisp dollar bill is 15.5 cm in length. Assume that you hold a bill so that another has
their sum and index finger at the middle of the bill. Given the information you found above would
you be willing to bet that they can’t catch the bill if you release it suddenly? Explain your answer.
Try it a few times to see if you are correct and report the results.
4
Name
Laboratory Section
Error worksheet
(Maybe useful for calculating uncertainties during the lab)
5