Objective:

Students will be able to compare and contrast the physical attributes of stars and planets, and construct an argument on why some stars (including the Earth’s sun) appear to be larger or brighter than others.

Materials:

• The Solar System: Inner and Outer Planets article by Floyd Brooks (or a similar text)
• Chart paper or whiteboard
• Markers
• Index cards
• Ruler
• Procedure:

Introduction (10 minutes):

• Begin by asking students if they know what a star and a planet are.
• Show them a picture of the Sun and ask if they know what it is. Explain that the Sun is a star, and it is the closest star to Earth.
• Ask students if they have ever wondered why some stars appear to be larger or brighter than others. Explain that today, they will be learning about the physical attributes of stars and planets and why some stars appear to be larger or brighter than others.

Activity 1: Inner and Outer Planets (20 minutes)

Give each student a copy of The Solar System: Inner and Outer Planets article by Floyd Brooks (or similar article/ text).
Ask them to read through the article silently and underline or highlight important information (Depending on the reading level of the students and the grade, it may be a good idea to read through the text with the students and go over unfamiliar words).
Discuss with the class the difference between inner and outer planets, and ask students to name each planet in order from the closest to the Sun to the farthest away.
Using chart paper or a whiteboard, create a chart with two columns labeled “Inner Planets” and “Outer Planets.” Have students come up and write the names of each planet under the correct column.
Discuss the physical attributes of each planet and ask students to compare and contrast them. For example, “Which planet is the closest to the Sun? Which planet is the largest? Which planet is the smallest? Which planet spins on its side?”
Use index cards to write down one physical attribute for each planet. Mix them up and have students draw a card, then come up to the chart and place the card under the correct planet.

Activity 2: Constructing an Argument (25 minutes)

Review with students the concept of distance and size when it comes to stars.
Ask students why some stars appear to be larger or brighter than others. Encourage them to use what they have learned about distance and size to construct an argument.
Divide the class into small groups and give each group a ruler and two balls of different sizes (e.g. a tennis ball and a soccer ball).
Ask students to measure the diameter of each ball and then hold them at different distances from their eyes. Ask them which ball appears larger and why.
Have each group come up with an argument for why some stars appear to be larger or brighter than others. They should use their knowledge of distance and size to support their argument.
Each group presents their argument to the class.

Conclusion (5 minutes)

Review the physical attributes of stars and planets, and why some stars appear to be larger or brighter than others. Students may make an entry into their science journals.
Ask students if they have any questions or if there is anything they would like to add.

Assessment:

Students will be assessed on their ability to compare and contrast the physical attributes of stars and planets, and construct an argument on why some stars (including the Earth’s sun) appear to be larger or brighter than others.

Students will turn in the completed quiz located at the end of the article.

Extension:

Students can research the different stages of a star’s life cycle and create a timeline or poster to present to the class.

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