Patrick M. Len
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pdog.bsky.social
Patrick M. Len
@pdog.bsky.social
33 followers 3 following 36 posts
Physics/astronomy instructor, Cuesta College, San Luis Obispo, CA. 🔭
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pdog.bsky.social
"Good Night, Low-Mass Star"
(h/t "Goodnight Moon" by Margaret Wise Brown)

A bedtime story for my introductory astronomy students, as an easter egg at the end of the nucleosynthesis presentation video.
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October 15, 2025 at 10:19 PM
pdog.bsky.social
Using the nucleosynthesis processes diagram with the nucleosynthesis periodic table for uranium, identifying merging neutron stars as the nucleosynthesis process that produced it.
Nucleosynthesis diagram identifying merging neutron stars as nucleosynthesis process that produced uranium.
March 2, 2025 at 6:37 AM
pdog.bsky.social
Using the nucleosynthesis processes diagram with the nucleosynthesis periodic table for xenon, identifying merging neutron stars and dying low-mass stars as nucleosynthesis processes that produced it.
Nucleosynthesis diagram identifying merging neutron stars and dying low-mass stars as nucleosynthesis processes that produced xenon.
March 2, 2025 at 6:35 AM
pdog.bsky.social
Using the nucleosynthesis processes diagram with the nucleosynthesis periodic table for aluminum, identifying exploding high-mass stars and exploding white dwarfs as nucleosynthesis processes that produced it.
Nucleosynthesis diagram identifying exploding high-mass stars and exploding white dwarfs as nucleosynthesis processes that produced aluminum.
March 2, 2025 at 6:33 AM
pdog.bsky.social
Key nucleosynthesis processes for my introductory astronomy students, in order to identify the processes that produced each of the elements.

flic.kr/p/2qPACcJ
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Nucleosynthesis Chart, showing four different processes: exploding high-mass stars, exploding white dwarfs, merging neutron stars, and dying low-mass stars. Not shown are big bang fusion, and cosmic ray fission.
March 2, 2025 at 6:30 AM
pdog.bsky.social
A simplified nucleosynthesis table, denoting the origin (but not relative amounts from each process) for each element. (Adapted from: Jennifer A. Johnson, "Populating the Periodic Table: Nucleosynthesis of the Element," Science, vol. 363 no. 6426 (1 February 2019)).

flic.kr/p/2qPu5NA
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A nucleosynthesis table, denoting the origin of each of the elements (adapted from: Jennifer A. Johnson, "Populating the Periodic Table: Nucleosynthesis of the Element," Science, vol. 363 no. 6426 (1 February 2019)). Relative amounts contributed by each process for each element have been omitted for the purposes of only identifying processes for each element. Also omitted: cosmic ray fission ("by-products from non-star processes").
March 2, 2025 at 6:28 AM
pdog.bsky.social
Star stage diagram for my introductory astronomy students, the roadmap for our deep dive into watching stars grow up, and watching stars grow old.

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Star Stage Diagram for high-mass, low-mass, and very-low-mass red dwarfs. Not to scale, stages past white dwarf and red dwarf not shown.
February 23, 2025 at 5:47 PM
pdog.bsky.social
Students are provided the International Astronomical Union classification questions, in a flowchart format.
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International Astronomical Union classification questions, in a flowchart format, with a schematic representation of planet orbits, asteroid belt, and Kuiper belt in the solar system.
February 18, 2025 at 6:02 PM
pdog.bsky.social
Case study (fictitious) for introductory astronomy students to classify: "Haelym (2025 PD6) recently captured the asteroid Moem, making it its moon. This moon-capture process permanently damaged Haelym's surface."

Determine how Haelym (2025 PD6) should be classified now.
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Artistic depiction of Haley (2025 PD6) orbited by Moem (2025 Q7).
February 18, 2025 at 6:00 PM
pdog.bsky.social
Space X launch this morning, with a waning crescent moon and Scorpius! 🔭
January 24, 2025 at 2:51 PM
pdog.bsky.social
First day of introductory astronomy class! Going with the tried-and-true "Marketplace Astronomy" activity. Adapted from D. Schatz, "Why Should We Care About Exploding Stars?" Universe in the Classroom, no. 8, (spring 1987), astrosociety.org/file_download/inline/4fe17a73-1ab8-4a34-b28c-bfe9267bdb90 🔭
Marketplace Astronomy worksheet: 1. Group sign in. 2. List car makes/models, foods, and non-food brands related to astronomy (share these later). 3. What are you interested in astronomy? 4. What do you expect to be confusing in astronomy? 5. Ask a question about this course (turn in, class discussion next!).
January 22, 2025 at 10:58 PM
pdog.bsky.social
November 11, 2024 at 1:41 AM
pdog.bsky.social
Student worksheets:
November 11, 2024 at 1:40 AM
pdog.bsky.social
November 11, 2024 at 1:38 AM
pdog.bsky.social
Student worksheets:
November 11, 2024 at 1:38 AM
pdog.bsky.social
Additional solar system objects (Ceres, Chariklo, Ryugu, 300163 (2006 VW139), 2019 LF6, and a theorized primordial black hole) for students to sort using the International Astronomical Union classification questions. 🔭

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Various solar system objects (Ceres, Chariklo, Ryugu, 300163 (2006 VW139), 2019 LF6, and a theorized primordial black hole).
November 9, 2023 at 5:08 PM
pdog.bsky.social
Various solar system objects (Ceres, Vesta, Cruithne, Gonggong, Phobos, Mercury, the moon, and Pluto) for students to sort using the International Astronomical Union classification questions. 🔭

flic.kr/p/2peMhi3
Various solar system objects (Ceres, Vesta, Cruithne, Gonggong, Phobos, Mercury, the moon, and Pluto).
November 9, 2023 at 5:07 PM
pdog.bsky.social
Student worksheet with instructions for sorting objects in our solar system (moons, solar system debris, dwarf planets, and planets) using the International Astronomical Union classification questions. 🔭

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Map of the solar system planets and debris belts, International Astronomical Union classification questions and classification flowchart.
November 9, 2023 at 5:04 PM
pdog.bsky.social
Turning this "Observable Universe" diagram 180° results in a "Looking Out, Looking Back In Time" diagram. 🔭

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A diagram from the cosmic microwave background (14 billion years away) to here, and when rotated 180°, it becomes a diagram from now to the cosmic microwave background (14 billion light years away).
November 8, 2023 at 3:47 PM
pdog.bsky.social
History of the universe from the early metal-poor stars, to the later metal-rich stars. 🔭

Stars eat hydrogen,
stars poop metals,
and we are made of starpoop.

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Above: "The Early Universe," a horizontal row of four comic strip panels of metal-poor star stages. Below: "The Later Universe," a horizontal row of four comic strip panels of metal-rich star stages.
November 7, 2023 at 4:54 PM
pdog.bsky.social
Physics midterms!
Me: Attach your single-sided handwritten study sheet to the exam when you turn it in.
Student: (Attaches Möbius strip study sheet to exam.)
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Physics equations written on Möbius strip staples to an exam.
October 16, 2023 at 10:01 PM
pdog.bsky.social
Sun-path diagrams for students to compare differences between here in San Luis Obispo, CA with Honolulu, HI, and Stockholm, Sweden. (Also making connections with solargraphy as well.) 🔭
Sun-path diagram for San Luis Obispo, CA, compared to sun-path diagram for Honolulu, HI. Sun-path diagram for San Luis Obispo, CA, compared to sun-path diagram for Stockholm, Sweden.
October 16, 2023 at 6:06 PM
pdog.bsky.social
Worksheet for students to work in small groups on identifying the moon position and locating the appropriate observer for different eclipse type. Each group is given two metal washers, and they discuss how to place those washers, followed by a whole-class discussion. 🔭
Side views of Earth and the moon, with sunlight entering from the left edge of the page. The Earth and moon both have their respective umbra/penumbra/antumbra shadow zones behind them (to the right) with additional notes on various eclipse types and configurations.
October 13, 2023 at 7:59 PM
pdog.bsky.social
An astronomy magazine article: 
"Every year, the constellations Canis Minor and Canis Major come to their early-evening peak of visibility in the night sky as winter winds down."

Modeling for students how to use a starwheel to determine a plausible date and time for this observation. 🔭
Picture of a starwheel with Canis Major and Canis Minor on the meridian, with a written explanation of finding a plausible "night sky" time and "winter winds down" date to make this observation.
October 12, 2023 at 5:03 PM
pdog.bsky.social
For my astronomy students this semester, even more than learning how to do sun-sign and rising-sign astrology with their starwheels, they really liked the Barbenheimer tie-in. 🔭
Instructions on how to find Barbie's astrological sun-sign and rising sign, with a birthday of March 9, 1959 at 10:00 AM. Instructions on how to find J. Robert Oppenheimer's astrological sun-sign and rising sign, with a birthday of April 22, 1904 at 8:15 AM.
October 11, 2023 at 2:31 PM