PT13.S4.Q5- "Planetary bodies differ from.."

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• 1 Like

  canihazJD Alum Member Sage ⭐

  October 2020 edited October 2020 8491 karma

  Let me give this one a shot because it's a great question to try and explain even if you can get it right under time. I ran it in a problem set first then BR'ed to get the full effect. Hopefully got it right o_O.

  My stimulus breakdown:

  PB have different compositions.

  Most PB in the solar system have solid surfaces.

  Unless the core of a PB has enough heat to cause volcanic action its surface won't be renewed for millions of years.

  If a PB with a solid surface has a surface that isn’t renewed for millions of years, it becomes heavily meteor cratered cratered - like the moon.

  Some old PB have solid icy surfaces with few meteor craters - like europa.

  Conditional Logic:

  PB -m→ solid this is a distractor

  1. Renewed → heat for VA (/heat for VA → /renewed)

  2. (Solid surface + /renewed) → heavily meteor cratered (/heavily meteor cratered → /solid surface or renewed)

  3. PB (cold) ← s→ solid icy (icy is a distractor) + few meteor craters (/heavily meteor cratered)

  Don't see any obvious inferences. Answers:

  A - Moon → /icy.

  Not supported. We only know the moon is solid and not renewed, therefore heavily cratered by meteors. None of these conditions leads us to icy. Note: Test writer has target focus on distractor element. Also targets our preconceptions of the moon.

  B - /heavily pockmarked → /heat for VA.

  Nope. Heavily pockmarked ≠ heavily pockmarked by meteor craters. Either way, all we know is that if a PB isn’t heavily cratered by meteors, then it hasn’t been renewed or doesn’t have a solid surface. Note: Test writer has target your own assumption that heavily pockmarked is the same as heavily pockmarked by meteor craters. Other things can cause craters.

  C - heat for VA ←s→ /icy

  Not supported. Again targeting "icy" which gives us nothing. Note: distractor element again.

  D - Jupiter’s moons ←s→ heavily meteor cratered

  Not supported. The only thing we know about Jupiter's moons is that:

  • one of them is called Europa
  • Europa is cold
  • Europa has a solid icy surface. Remember this one.
  • Europa is not heavily pockmarked by meteor craters. Remember this one too.

  Could be targeting outside knowledge/assumptions about jupiter's moons... I dunno, are any of them actually known for being heavily cratered?

  E - PB(very cold) ←s→ heat VA

  This is correct. We know some PB (like europa) are 1. very cold and have solid icy surfaces and 2. not heavily cratered by meteors

  PB (very cold), some are:

  /heavily meteor cratered

  solid surfaces

  We also already have:

  /heat for VA → /renewed

  and:

  /renewed + Solid surface → heavily meteor cratered

  From the last statement, given Europa's solid surface (solid icy surface) :

  /heat for VA → /renewed → heavily meteor cratered

  Or

  /heavily meteor cratered → renewed → heat for VA

  Back to the top, Europa is very cold, and not heavily pockmarked by meteor craters, activating the above conditional. So:

  [Europa (PB + very cold +solid surface)] → /heavily meteor cratered → (renewed + solid surface)→ heat for VA

  I'm trying to illustrate that the given in the description of Europa gets used to activate the sufficient condition for heat for VA.

  So of all PBs at least Eurpoa, being very cold, is not heavily pockmarked by meteor craters, therefore has been renewed within millions of years (along with its solid icy surface), therefore has a core with enough heat for volcanic action. Note: time sink placement of this AC.

  @miriaml7

  Since it used the idea of "/renewed surface" , I was able to chain it up with the second sentence:

  /heat to cause volcanic action --->/renewed surface ------->heavily pockmarked

  When I got to the last sentence, I got lost. I didn't know how to diagram it. I feel like the last sentence plays a role in the chain from above, but I don't really know what that would look like.

  What you did here is leave out the "solid surface" element. /heat to cause volcanic action doesn't chain all the way through to heavily pockmarked unless you have "solid surface"along with /renewed surface (both of which are required as the sufficient condition of heavily cratered), which is coincidentally what the last sentence gives you.

  I think the last sentence could have gone:

  PB → old ←s→ very cold + solid icy surface + /heavily pockmarked

  or

  [Europa (PB + old + very cold +solid icy surface)] → /heavily pockmarked

  Both of which are different than how I did it up top. Not sure which if any is better or more correct, but I think the important thing being you identify that there is a PB that is very cold and has a solid surface.

  Everyone else please let me know if you see something I missed! Doesn't seem to be a video for this one, but it's a great question to discuss. @miriaml7 thanks for posting it, let me know if this helped! Gonna take a break and let it marinate for a while (usually helps to see if I did anything stupid), then check the answer.
• 1 Like

  miriaml7 Live Member

  October 2020 edited October 2020 1025 karma

  This is such an awesome explanation!! Thank you so much for taking the time to write it!!

  I think the fact that there were a lot of descriptive words for the separate ideas that were being represented in a conditional relationship, made it really hard for me to chain this up smoothly. For example, when I got to the last sentence I didn't know if Europa having a "solid ICY surface" made it distinct from planetary bodies that have "solid surfaces." I also didn't know if it having a cold moon and having few meteorite craters were of importance.

  I think this factored into why I left out the idea of "solid surface". When I read the second sentence, particularly the part about planetary bodies, "with a solid surface whose surface is not renewed for millions of years," I placed a higher emphasis on "renewed surface." The reason I did this is because I thought the statement was making a distinction between solid surfaces that have not been renewed and all other solid surfaces.Clearly, this wasn't relevant. I really tend to do a lot of overthinking:/

  Any tips on how to not get so caught up on the "fluff" of a stimulus?

  Again, thank you so much for the explanation. @canihazJD
• 1 Like

  canihazJD Alum Member Sage ⭐

  October 2020 edited October 2020 8491 karma

  @miriaml7 It was just as beneficial for me! I think you just have to get used to the fact that these are tricks the test writers will employ to increase the difficulty of a question.

  • Throwing in conditionals that are unnecessary - most planetary bodies are solid.
  • Adding distractor elements to camoflauge shared conditions - solid icy surfaces
  • Emphasizing one descriptive aspect of a critical element (pockmarked) to prime you to accept a trap answer (B)
  • Hiding the compatibility of the given conditionals by supplying parts of a compound sufficient condition separately - solid surfaces and not renewed.

  I'm sure there's more. I do know that all of these techniques are used at least separately in many other questions. Just be aware that it occurs and eventually you will start to notice those tripwires before you walk into them, just as we do for common flaws like source attacks, appeal fallacies, etc..

  This is such a great question... I want to find more like it. Does anyone else have any?
• 1 Like

  miriaml7 Live Member

  October 2020 1025 karma

  You're awesome! Appreciate all your help!! @canihazJD