8th GradeDilationsabout 2 minCCSS 8.G.A.4Understand that a two-dimensional figure is similar to another if the second can be obtained from the first by a sequence of rotations, reflections, translations, and dilations; given two similar two-dimensional figures, describe a sequence that exhibits the similarity between them.CCSS 8.G.A.5Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles.+0
How a small Moon hides a huge Sun.
Lesson Plan
Explore dilations and similar figures by relating an object's size, its distance and its apparent size.
Question: Ask what students spot and what they are curious about. Read “At arm's length, which matches the full Moon?” aloud. Have each student guess and say why.
Big idea: Pause. Ask a student to say the idea in their own words.
Question: Read “What happens to total eclipses, someday?” aloud. Have partners explain their guesses to each other.
Real-world application: Ask: Where else have you seen this?
Your turn: Have students try their own. Ask them to predict before they test.
How to run it
Whole classPut the lesson on the board. At each choice the class votes, then you select the winner.
SoloShare the link, QR code, or post to Google Classroom. Each student gets to take their own path.
