Is Pluto a Planet?
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Objective
I can argue whether Pluto should be classified as a planet using evidence and reasoning.
Part 1 of 4
Warm-up video
NASA Science · 7:54Vetted channel
We don't generate video — this one is by NASA Science on YouTube. The practice questions and exit ticket below were drafted by AI for this objective, and every question is editable in the teacher guide.
Part 2 of 4
Key concepts
3 concepts
- 1
The ancient Greeks called objects that moved against the background of stars 'planetes', meaning wanderer.
- 2
According to the IAU, a planet must orbit the sun, have sufficient mass to be nearly round, and clear its neighborhood of other objects.
- 3
Pluto is considered a dwarf planet because it has not cleared its neighborhood and resides in the Kuiper Belt.
Part 3 of 4
Practice
12 questions
Before the 20th century, what was the primary method for distinguishing planets from stars?
Why did the discovery of objects like Ceres, Pallas, Juno, and Vesta lead to a reclassification of celestial bodies in the 19th century?
Part 4 of 4
Exit ticket
Quick comprehension check
“Using evidence from the video, argue whether or not Pluto should be classified as a planet. Support your argument with at least two specific reasons.”
Sample answer included in the free materials
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Teacher guide, student handout, and slides — free, in Google Docs format
Teacher Guide
Complete lesson plan with answer keys and alternate activities
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