Lesson Plan

Poor Pluto

A celestial exploration of Pluto’s declassification from "planet" to "dwarf planet"
Darri S.
Senior Director, Education Content Common Sense Education
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Objectives

Students will be able to...

  • recite the eight planets in order from the sun.
  • identify characteristics of the dwarf planet Pluto.
  • summarize why Pluto lost its classification as a “planet.”
Subjects
Science
Grades 3 - 5
All Notes
Teacher Notes
Student Notes

1 Hook

Activity: Creating

Remind students that previously you all have talked about the eight planets found in the Solar System. Explain how, when you were younger (before 2006), the world thought that there were nine planets in the Solar System. In learning about the planets’ order from the sun, you learned the mnemonic device (a technique that helps one’s retention of facts):

My Very Excited Mother Just Served Us Nine Pizzas

Point out how this sentence maps to the order of (formerly nine) planets:

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto

However, in 2006, Pluto was declassified as a planet, so now a new mnemonic device is needed. Have students brainstorm individually about a “new” mnemonic device/phrase to help remember the order of the planets from the sun: M, V, E, M, J, S, U, N.

Student Instructions

Create your own mnemonic device to help you remember the eight planets, in order from the sun. Make it something that’s easy for you to remember!

Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune

2 Direct Instruction

Ask students why they think or what they’ve heard about why poor Pluto is no longer considered a planet. Next, show Ask an Astronomer’s Why Isn’t Pluto a Planet Anymore? (3:31) via SchoolTube. Using the video as a jumping off point, explain how/why Pluto has been declassified as a “planet,” and now is reclassified as a “dwarf planet.” Consider using the multitude of images available online and in books to highlight the following comparisons and contradictions:

  • Pluto never really “matched” the other eight planets:
    • has a solid core and frozen surface (unlike other gas giants)
    • much smaller (@1600 mi. in diameter) than other outer planets
    • has elongated, tilted orbit which crosses that of Neptune
    • formed later than other eight planets (actually part of Kuiper Belt)
    • far from the sun (orbit is 248 Earth years; if a sheet of toilet paper represented 10M miles, Pluto would be 366.4 sheets from the sun)
  • Yet Pluto is similar to Eris, Ceres, UB 313/Xena
  • Discuss how in 2006, the International Astronomical Union (IAU) set the following definition for a planet in our solar system:
    1. must orbit the sun
    2. be sphere/ball-like (due to gravity)
    3. and have an orbit that clears its neighbors
Student Instructions

Watch the video, "Why Isn’t Pluto a Planet Anymore?" on SchoolTube.

Take notes and record facts on why Pluto was declassified from a “planet” to a “dwarf planet.” 

3 Guided Practice

Glogster
Free to Try, Paid

Divide students into collaborative groups. Introduce them to GlogsterEDU, a tool to create multimedia, digital posters. Take a few minutes to share other students’ work samples from the gallery to highlight how photos, drawings, audio clips, hyperlinks, graphics, videos, and text can be featured. Ask students to create digital posters explaining why Pluto was demoted and reclassified as a “dwarf planet” (possibly curate a collection of appropriate images and videos beforehand to share with students).

Consider creating a rubric outlining that digital posters must include the following criteria:

  • Poster title
  • Astronomers’ (students’) names
  • Definition of a planet
  • At least three facts about Pluto
  • At least three images that show Pluto
  • At least three reasons why Pluto was reclassified
  • Related outer space fun fact
  • A “new” mnemonic device for the order of the planets from the sun
  • Optional: embedded video, audio clip, hyperlink to related website
  • Bonus challenge: include an audio clip of group singing Sesame Street’s “One of these Things (Is Not Like the Other).”

One of these things is not like the others,


One of these things just doesn't belong,


Can you tell which thing is not like the others


By the time I finish my song?

Did you guess which thing was not like the others?

Did you guess which thing just doesn't belong?

If you guessed this one is not like the others,


Then you're absolutely... right!

Student Instructions

In your group, create a digital poster answering this question: Why is Pluto now called a “dwarf planet” and not a “planet”?

Collect evidence: facts about Pluto, images, links to credible websites, and video to support your claim.

Together, use GlogsterEDU to create your poster.

Your poster needs to have:

·       Poster title

·       Astronomers’ (students’) names

·       Definition of a planet

·       At least three facts about Pluto

·       At least three images that show Pluto

·       At least three reasons why Pluto was reclassified

·       Related outer space fun fact

·       A “new” mnemonic device for the order of the planets from the sun

*Optional: embedded video, audio clip, hyperlink to related website

**Bonus challenge: include an audio clip of group singing Sesame Street’s “One of these Things (Is Not Like the Other).”

One of these things is not like the others,

One of these things just doesn't belong,

Can you tell which thing is not like the others

By the time I finish my song?

Did you guess which thing was not like the others?

Did you guess which thing just doesn't belong?

If you guessed this one is not like the others,

Then you're absolutely... right!

4 Independent Practice

BrainPOP
From $220

Have students watch BrainPOP’s Pluto video. Ask students to take the Graded Quiz and print/email their individual results. If time permits, they can explore the video’s other offerings: Q&A, Activities, FYI, Experiment, and Timeline. 

Student Instructions

Watch the Pluto video on BrainPOP. Take the quiz after the video, and email your results to me.

Done early? Look at the Q&A, Activities, FYI, Experiment, and Timeline on BrainPOP.

5 Wrap-Up

Encourage families to explore NASA’s Space Place and search for content related to Pluto. Under Activities for the Classroom, there is a downloadable PDF, Pluto or Bust!, about NASA’s New Horizons mission to Pluto-Charon (launched in 2006, expected arrival in 2015). Family members can discuss the concluding questions or create their own list of questions that they are hoping to have addressed by New Horizons.

Student Instructions

Take home the “Pluto or Bust!” Handout to your family. Talk about what questions you would want the New Horizons mission to answer.