The VOLVO Rule: When troubleshooting, turn only ONE knob at a time!





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Notes from the lecture:

  1. Advanced Knobs & Needles: Thinking About Experiments
  2. FAQ: Do we need to use Python and/or am I not allowed to use KGraph/Excel?
    • No – but the quality and completeness of your data analysis should not be limited by your choice of tools not designed for the task at hand.
    • Taking the time to learn how to use a professional scientific tool is a long term investment in yourself and a sign of self-respect.
  3. Reminder: Grading & Due Dates
    • Logbooks are due in two weeks on Friday Oct 6 @ 1600.
    • 1st draft of final paper does not have to be good, but it does have to be complete.
  4. BPS 4216 & NSCL Lobby
    • Tuesday section due at BPS 4216 – JP office
    • Thursday section due at NSCL Lobby – JTS office
  5. Daily Meditation: Failure is a gift.
  6. The VOLVO Rule: When troubleshooting, turn only ONE knob at a time.
    • Take the time to systematically troubleshoot your apparatus. This valuable process is how you learn the experiment.
    • Is it plugged in?
    • Is it turned on?
    • Is it broken?
    • What assumptions am I making?
    • Do I know what I’m talking about?
    • Are there secret knobs?
  7. & 8. Stanislav Petrov: The Man Who Saved The World By Thinking
    • NPR Story
    • BBC News
    • Petrov was a Russian Army officer who was responsible for alerting Moscow if the Early Warning System detected missiles from the USA.
    • In 1983, this system warned of the launch of 5 missiles, given Petrov about 20 minutes to react before impact.
    • Because there was conflicting information and the data did not make sense, Petrov decided to not call Moscow thereby preventing the USSR from launching a retaliatory missile launch towards the USA.
    • After twenty minutes, nothing happened which indicated that he had made the correct decision.
    • Petrov: “There was no rule about how long we were allowed to think before we reported a strike.”
    • Interesting tidbit – Petrov received an official reprimand, not for the actions that he didn’t take that day, but for mistakes in his logbook.

9., 10., & 11. – see this post on producing scientific diagrams.

  • A photograph is usually uninformative…
    • …except when capturing a phenomenon (a sonoluminescent bubble or fluorescence from an atomic vapor cell)
    • …or when recording complex knob settings and cable arrangements
    • …or when clarifying what a broken (before) and fixed (after) piece of equipment looks like
  • labeled boxes are much better, but…
  • a semi-representational schematic with relevant equipment specifications is the best.

12a. Model of Measurement System:

  • What are all of the components?
  • Is it a knob or a needle?
  • Are there photons?
  • Do we have a knob that controls the energy and/or number of photons? (These are related but are not the same thing.)
  • Do we have a needle that the energy of the photons and/or counts the number of photons?
  • Are there electrons?
  • Do we have a knob that controls the number of electrons and/or needle that counts the number of electrons?
  • How do we record the knob settings?
  • How do we record the needle settings?

12b. Model of Physical System:

  • Is there an energy level diagram?
  • Do we have a knob that controls the energy levels of the system?
  • Which knob am I turning to study the system?
  • Which needle indicates that the system has changed in some fundamental way?

12c. Cartoon Game – I hand draw a cartoon schematic for every experiment which captures just the essential aspects of the measurement (knob & needles) and physical (energy level diagrams) systems. A great example is here:

  1. Questions to Ponder Abouts Knobs & Needles
  • What do the knob and needle represent?
  • What determines the appropriate scale for the knob setting and needle reading?
  • What is the appropriate range of values for the knob setting and needle reading?
  • How well do we know the knob setting and needle reading?
  • What is your prediction for the shape of the needle vs. knob curve and why?