Reading Comprehension

PT115 · S3 · P3 · Q23 Planck and Wave Theory

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With the approach of the twentieth century, the classical wave theory of radiation—a widely accepted theory in physics—began to encounter obstacles.

Topic

Wave theory of radiation

Framework

old / new

Paragraph 1 The very first sentence warns us that we're probably reading an Old/New type passage (along with the fact that Old/New is the most common framework for Science) passages.

An accepted theory is encountering obstacles?

When you suspect an Old/New framework, you try to proactively predict the New, by defining it as the logical opposite of the Old (in the hopes of priming your brain so that it's easier to process the payoff sentences when they arise).

Old New all EM radiation exists some EM radiation in the form of waves isn't in wave form?

as length of wave as length of wave shortens, its energy shortens, its energy increases smoothly doesn't go up like (volume dial) a smooth volume dial?

Any conceivable some energy values energy value could can't occur in occur in nature nature?

Paragraph 2 The transition sentence warns us that we're about to hear the story of the "obstacles" that wave theory started to encounter. Many science passages with an Old/New structure have a section where they're saying: Scientists thought / assumed X, which meant that Y should be true. But then data showed that Y wasn't true!

This happens when we hear that physicists originally predicted they would find more energy at short wavelengths, however they found almost none.

This tension is what sets us up for the New.

Paragraph 3 The second sentence gives us Planck's answer to this conundrum -- "get rid of the Old volume dial / continuous view of energy, start using a New incremental-click / discontinuous view".

We even get a mini Old/New at the end of the paragraph as we learn that "at first" the physics community was deeply reluctant to accept this, since Planck had no physical explanation to back this up.

Paragraph 4 This paragraph opens with a continuator that says Einstein and others came to the rescue by coming up with a different theory of energy that could explain why Planck's incremental-click / discontinuous view could be legit.

The big breakthrough here was the idea of positing particles (photons) that are discrete units and certain wavelengths. (a particle is a quantum of energy, a specific quantity of energy ... which is where the name quantum physics comes from )

23.

The passage is primarily concerned with

  1. discussing the value of speculation

    Too Broad

    This passage is definitely about Wave Theory and Planck, not a broad discussion on "the value of speculation in science". If you showed up for a workshop called "the value of speculation in science", you'd expect to hear more than one example.

    3% picked this

  2. summarizing the reasons for the

    Not a Summary of Reasons

    This tells the story of an intrepid thinker who solved a riddle and made scientists drastically rethink an established theory. It wasn't a summary of reasons the scientific community rejected this theory. It was the story of the scientist who solved the riddle that allowed the scientific community to move beyond this theory.

    24% picked this

  3. describing the role that experimental

    Too Broad

    Just like (A), this primary concern sounds like a sprawling conversation about science in general, not a specific retelling of a pivotal advance in physics around 1900.

    6% picked this

  4. Correct

    examining a critical stage in

    Why this is right

    The beginning of the 1900s was a critical stage in the evolution of theories concerning the nature of the physical phenomenon known as electromagnetic radiation. Is this passage primarily concerned with examining a critical stage in the evolution of theories concerning radiation? Yes! In fact the final sentence, which sounds like the best one sentence takeaway we'll find in the passage, says "in just a few years (critical stage) what was considered catastrophe generated a new vision (evolution of theories)".

    Skill tested: Primary Purpose · how this choice captures the passage's function is the move to repeat next time.

    65% picked this

  5. comparing the various assumptions that

    Not about Assumptions

    Even though the 2nd paragraph discuses a major assumption of Wave Theory in order to help us better understand the confusing experimental data that suggested to physicists that Wave Theory was missing something, the primary focus of this passage is not assumptions. In fact, we really only cover "One fundamental assumption of wave theory" (smooth, any value). A passage that compares various assumptions would detail several assumptions at the foundation of physics and relate them to each other. This passage was a story about how one specific assumption got overturned by the Big Dog, Max Planck.

    2% picked this

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