PHY 2092 Distance Learning Experiment Guide
YouTube Video #1
This 5:37 video is fun to watch and the background music can be used to help you go to sleep! But don’t
nod off. After watching the video, choose two of the demonstrations, describe them in writing and then
explain the physics in the discussion section of your report.
The GSA making the videos listed below also took many still photos of the pieces of equipment used in
this experiment. These photographs can be found in Canvas > Files > Experiments > 01 Electrostatics.
In the data analysis section of your report, create a table. In one column, list the file name of each
photograph and in the next column, write the technical name of each piece of equipment.
All of these videos (except the YouTube video) have been intentionally recorded withOUT any narration or
Watch the videos with these file names by going to the lab’s Canvas course and Click on Panopto
Recordings > Exp 01 Electrostatics. Read the procedure for Part 1 and watch these videos in the
alphabetical order listed. You may need to watch a video more than once. Determine which procedure
number corresponds to each video. In your discussion section, create a table that lists both the file
names and the procedure number.
Pt 1 a.mp4
Pt 1 b.mp4
Pt 1 c.mp4
Pt 1 d.mp4
Pt 1 d.mp4
The data to take for this experiment is the readings of the electrometer shown in the videos. This is not a
very quantitative experiment. Use the following and draw conclusions from the brief videos.
Color of Pad Trial 1 (Volts) Trial 2 (Volts) Trial 3 (Volts) Trial 4 (Volts)
White 3 3 2 2
Blue -4 -4 -4 -4
Both -1 -1 -1 -1
Both (touching) 0 0 0 0
Watch the videos with these file names in Panopto Recordings > Exp 01
Pt 2 a.mp4
Pt 2 b.mp4
Again, determine which procedure number corresponds to each video and list both the file names and the
procedure number in your discussion. Additional Question: For Pt 2 b.mp4, what could the
experimenter have done to see a larger deflection of the LED in the electrometer?
YouTube Video #2
It is recognized that these brief videos may be too limited to give the beginning Lab 2 student sufficient
clues to draw conclusions. Therefore the link to this YouTube video is provided so the student can pull
these ideas together in Part 2.
Go to the website mentioned in the procedure and complete the activities in Part 3. White a brief
description of each activity. Include a screen capture for each activity. Place these in the Discussion
section of your report.
Charge source Electrometer Reading (Volts)
Side near to first sphere -15
Side far from first sphere 15
Side far from first sphere after ground 0
Data Analysis Sample Calculations:
These are good examples of how to set up your sample calculations in the Data Analysis section of your lab reports. These are single calculations from various students’ reports. The reports should include sample calculations, set up like these ones, for every type of calculation done during an experiment. These calculations would all get full credit but if you are looking to have outstanding calculations you should also discuss how these equations relate back to the physics concepts of the lab and why they are essential to the experiment.
The slope of the best-fit line on the range vs. velocity graph represents the function of the time of flight in seconds. The following equation uses the height from which the ball falls from, h, and the local acceleration of gravity, g, to solve for the theoretical slope, or theoretical time, xt.
xt = = 0.445 s
The equation [the equation for projectile motion previously stated] can be rearranged to solve for the time, t, by multiplying both sides by two, dividing both sides by the gravitational acceleration, g, and taking the square root of both sides.
Formula 5. Formula 4 changed to solve for the time.
By replacing the values with the measured values of the height, h, from the floor to the end of the track and of the gravitational acceleration in Melbourne, FL, we can get the ideal time.
Formula 6. Theoretical time for the metal ball to get in contact with the floor.
This is a sample calculation for the theoretical time (tth) using the height of the ramp (h) and the gravitational acceleration (g).
Slope = √(2*h/g)
Slope = √(2*.98/9.7929) = .447 (s)
Sample calculation of time. The time can be calculated by , where h is the height and g is the gravitational acceleration. By using the theoretical value of gravity, this will calculate the theoretical value of time. This will later be compared to the experimental value of time.
Determining The Theoretical Value of Time
The theoretical value of time is found by rearranging an equation that uses constants in the experiment. For the distance in the Y direction this formula, derived from the projectile motion equation, is used and it can be rearranged to find the theoretical time.
The values from the experiment are plugged in and used to solve time.
The experimental slope, or time, is gotten from the equation that we got from the graph of the Range vs. Velocity which was graphed and calculated by excel. The experimental slope is the multiple of the x in our equation.
Equation of the slope: y=0.3974x + 0.0184. As we know the equation of a slope is y=ax + b, 0.0184 is our b that is known as y-intercept which is the initial position and 0.3974 is the slope, a, the experimental flight time. R2=0.99855. As much as R2 is closer to 1, it is better. Our R2 is very close to one which shows our good accuracy in doing the experiment.
t’= theoretical slope h= average hight g= local acceleration due to gravity
t’= (2(0.9563))/9.792 = 0.442
Discussion of Errors:
These are examples of how to completely discuss the errors in your experiment. Each paragraph here discusses a single error, your lab reports should discuss all errors in your experiment (hint: there is always more than 2). In both these paragraphs the error is described and categorized, and how the error affects the results/other parts of the experiment is discussed.
The primary source of error was intrinsic systematic error in the shaping of the track, as it was slightly sloped in the final stretch right before the photogate, so index cards were needed to make this part of the track level. This paper may not have been completely level, resulting in instability in the track and inaccurate measurements of the ball’s range. A more stable track setup could be used that lacked this instability in order to procure more accurate results and measurements.
There were sources of error that took place in the experiment that caused inaccuracies in the results. The angle measurement was based on the location of the angle scale. It was hard to align the scale with the protractor perfectly. Because of this, it was difficult to get a good accurate measurement of the angle. This is a systematic error in the measurement because there was a flaw in the tool process. This error impacted results and calculations because the angles were very important when it came to calculating the x and y components of each force. Also, the angles were very important when it came to constructing the vector diagrams.