Lab Skeleton
Aim:
The aim of this lab is to find the relationship between _____________ and
_________________ for a __________. How does increasing _____________ affect
_________?
(Or will _______________ increase, decrease, or remain the same as __________ is
increased.
Or to investigate which factors affect, increase, change ………
Hypothesis:
I believe that as ______________ increases _______________ will ___________
as a ____________ function. The graph of _______________ vs. ____________ will
show a ____________________ relationship.
Variables:
The independent variable will be _______________ and the dependent variable
will be ________________. Some other variables that could affect the experiment which
I will attempt to hold constant are ___________________, ___________________,
__________________, ________________, and ___________________________.
Procedure:
Materials List (be specific)
_____________ will be (varied, increased, decreased) as _____________________ is
measured using ____________________. A minimum of _______
___________________ will be tested. At least _____ trials will be performed for each
___________ until consistent data are acquired.
Explain how measurements were made and include the method you use to hold each
variable (from above) constant. Include a picture if desirable.
_________________ was held constant by ___________________.
Data
Tables:
Each column should include labels for units and the ± uncertainty at the top.
All values are recorded with correct sig fig’s which agree with uncertainty.
Decimals values only – no fractions.
Both raw data and averages are shown.
Include qualitative observations. Ex: “Sometimes the bouncy ball hit the wall or did not
bounce straight up”
Graphs.
Scaled evenly starting a zero where appropriate (check with teacher).
Each box should be equal to or twice the uncertainty if possible.
Error bars are included if possible. If not, write “error bars too small to be shown at this
scale”.
Plot points. Sketch error bars. Fit data with best fit line or curve depending on your
interpretation.
Curve/line should touch the bars.
Both axes must be clearly labeled with titles and show units and uncertainties.
Data Processing:
For each calculation.
Explain what you are calculating. In some cases you might have to offer a rationale. For
instance: “ the slope of a tangent to a point is being calculated to find the instantaneous
velocity from the d – t graph”.
Show equation.
Show values with units plugged in.
Show answer with units circled.
In some cases you will have many calculations to show.
Show calculation of absolute uncertainty and its propagation.
Note: in order to determine if a curve is square root or some other function you must replot the data or calculate a correlation coefficient. See your teacher.
Conclusions:
Give background material:
Say something about the physical behavior you observed. Ex:
A pendulum bob falls under gravity and is/is not an example of accelerated motion or
sound is a type of mechanical wave that is propagated by…………… or heat is
transferred between materials by the process of ………. . etc.
Say something about known laws:
Newton’s second law states that ……….. and so the expectation was that……….. or
equations: Accelerating objects have d vs. t graphs that are ……….
State known values: The acceleration of gravity on Earth is…….. or the heat constant is
……………
Discuss your data.
Looking at the graph(s) / data………… the trend of the data is…The data can best be fit
with a line/ quadratic curve/ square root curve/ inverse… not clear. Note: Make sure you
can fit the data correctly.
The equation that describes the relationship between ________________ &
______________ appears to be……… The trend does make/does not make sense
because………. You must analyze what’s happened in your experiment.
Give statistical information: The correlation coefficient for the function is……. And this
shows………
If you have known values you must calculate a percent deviation from a known value and
discuss it (ie: you know the value of g).
Discuss your original hypothesis. Was it supported? Why or why not?
Analyze sources of error in your experiment.
Look at your data set and graphs. Is the error random or systematic? Explain with relation
to your data and observations.
Give 2 – 3 obvious sources of error for your experiment. This does not include mistakes
in calculations! An obvious error source would be heat lost in a calorimeter, or energy
lost to friction. These types of errors must agree with the trend in your data. If you
consistently get a low value for g, then the error must cause that type of result! If a
velocity is too slow then friction is a good bet.
State realistic improvements that address that directly address the errors you stated. These
include better equipment. You can go online and look up similar experiments and
research the type of equipment available. You can’t remove air friction but you can
suggest ways to minimize it. Minimizing error rather than obliterating it shows
sophistication in your thought process.