Description
What our UnPlanets: Pluto lesson plan includes
Lesson Objectives and Overview: UnPlanets: Pluto is a high-interest reading comprehension lesson plan. As such, students will practice various close reading and comprehension skills. In addition, they will learn about this dwarf planet in our solar system. This lesson is for students in 3rd grade, 4th grade, and 5th grade.
Classroom Procedure
Every lesson plan provides you with a classroom procedure page that outlines a step-by-step guide to follow. You do not have to follow the guide exactly. The guide helps you organize the lesson and details when to hand out worksheets. It also lists information in the yellow box that you might find useful. You will find the lesson objectives, state standards, and number of class sessions the lesson should take to complete in this area. In addition, it describes the supplies you will need as well as what and how you need to prepare beforehand. The activity requires a number of supplies, including CDs, foam balls, and paperclips. You may want to cut the foam balls in half ahead of time.
Teacher Notes
The teacher notes page provides an extra paragraph of information to help guide the lesson and remind you what to focus on. It explains that you can teach this lesson in a whole-class setting or as an independent, small-group activity. The blank lines on this page are available for you to write out thoughts and ideas you have as you prepare the lesson.
UNPLANETS: PLUTO LESSON PLAN CONTENT PAGES
Introduction to Pluto
The UnPlanets: Pluto lesson plan contains three content pages. Once the ninth planet in our solar system, Pluto has a story as mysterious as its distant location. Discovered in 1930 by astronomer Clyde Tombaugh, Pluto was named after the Roman god of the underworld. Believe it or not, an 11-year-old English girl named Venetia Burney was the one who suggested the name. Pluto orbits the sun at an average distance of about 3.67 billion miles (5.9 billion kilometers) from Earth, making it one of the farthest known objects in our solar system.
Pluto is a tiny, icy world. It has a diameter of about 1,473 miles (2,377 kilometers), which is only about half the width of the United States. Its surface is covered with nitrogen ice, and its atmosphere is thin and consists mostly of nitrogen with traces of methane and carbon monoxide. The temperatures on Pluto are frigid, averaging around -375°F (-225°C). Interestingly, its surface has smooth regions, showing signs of geological activity, and heavily cratered areas, indicating a long history of impacts.
There are five known moons orbiting Pluto: Charon, Nix, Hydra, Kerberos, and Styx. Charon, the largest moon, and Pluto orbit each other like dancers spinning around one another on a stage. It is also so big compared to Pluto that the two are sometimes considered a double dwarf planet system. Charon is about half the size of Pluto and orbits it every 6.4 days. Scientists believe its surface is water ice, unlike Pluto’s icy nitrogen crust. The other moons are much smaller but still add to the intrigue of this distant world.
History of Pluto’s Demotion
When scientists discovered Pluto, they called it the ninth planet in our solar system. At the time, it fit the general understanding of what made something a planet; it orbited the sun. It was large enough to be shaped by gravity into a round shape. For more than 70 years, it held its place in textbooks and science lessons as the last planet in our solar system.
In 2006, however, the International Astronomical Union (IAU) created a new definition of a planet. To qualify, a celestial body must orbit the sun, be spherical in shape due to its own gravity, and have cleared its orbit of other debris. Pluto met the first two criteria but not the third. It shares its orbit with objects in the Kuiper Belt, a region of icy bodies beyond Neptune. Because of this, scientists reclassified Pluto as a “dwarf planet.”
The decision to demote Pluto sparked a worldwide debate. Many people, including astronomers, disagreed with the new definition of a planet. A few argue that Pluto’s unique characteristics, like its moons and atmosphere, make it special enough to still consider a planet. Others believe the new classification helps scientists better understand the variety of objects in the solar system. Some scientists think the classification helps distinguish between planets and the many small celestial bodies in the Kuiper Belt.
Effects of the Decision
For many people who are not scientists, Pluto’s reclassification was emotional. Generations grew up learning about Pluto as the ninth planet, and its demotion felt like losing a piece of childhood wonder. Some people still consider it a planet in their hearts and advocate for its return to planetary status. Others see the change as part of the exciting evolution of science, showing how much we’ve learned about the universe. Whether a planet or a dwarf planet, Pluto remains a beloved part of our solar system.
Even though Pluto is no longer a planet, it remains an essential part of our solar system’s story. Its reclassification led to the discovery of hundreds of other dwarf planets in the Kuiper Belt and beyond. These discoveries have expanded our knowledge of the solar system. Future missions might return to study its surface, moons, and atmosphere in greater detail. Every discovery adds to our understanding of the universe and our place in it.
UNPLANETS: PLUTO LESSON PLAN WORKSHEETS
The UnPlanets: Pluto lesson plan includes two worksheets: an activity worksheet and a practice worksheet. Each one will help students solidify their grasp of the material they learned throughout the lesson. You can refer to the classroom procedure guidelines to know when to hand out each worksheet.
THE GREAT DEBATE ACTIVITY WORKSHEET
For the activity, students will divide into groups and conduct a debate. You can assign groups which side of the argument they should debate: Pluto is a planet, or Pluto is not a planet. Groups will research evidence and supporting arguments for their side. Then they will participate in the debate.
UNPLANETS: PLUTO REVIEW PRACTICE WORKSHEET
The practice worksheet lists 10 questions based on the content. These questions all relate to the content pages, so students will need to refer to them often for the answers. In addition, each question provides which reading tool the question corresponds to, such as text feature, vocabulary, or comprehension.
Worksheet Answer Keys
At the end of the lesson plan document is an answer key for the practice worksheet. The correct answers are all in red to make it easier for you to compare them with students’ responses. If you choose to administer the lesson pages to your students via PDF, you will need to save a new file that omits these pages. Otherwise, you can simply print out the applicable pages and keep these as reference for yourself when grading assignments.
