No captions Captions Stop the video above first if it is playing.
No captions Captions Stop the video above first if it is playing.
Mary and Claire explore the path traveled by two people who live in different locations, Michigan and the Caribbean, as the earth makes a full rotation. They figure out how much of a rotation the earth needs to make for each person to travel 1,000 miles.
Episode Supports
Students’ Conceptual Challenges
Claire and Mary continue to make sense of how arc length and angle of rotation are related. As in the previous episode, the students engage with the task, which provides opportunities for learners to reason about angles of rotation by knowing the arc length and the radius of the circle. While Mary and Claire seemed ready to explore these ideas, some students might struggle to get started. Encourage your students to use diagrams and discuss what they know and what they want to find as they work through the task.
Focus Questions
For use in a classroom, pause the video and ask these questions:
[Pause the video at 0:54] Before watching Mary and Claire complete this task, try it for yourself. As the Earth rotates, you trace out a circle with a radius of about 2,000 miles while your friend in the Caribbean traces out a circle with a radius of about 4,000 miles. How much of a full rotation do you each make after you have travelled 1,000 miles?
[Pause the video at 3:46] Mary and Claire decided to calculate 1,000/12,566.37061. What will that fraction yield in the context of this task?
Supporting Dialogue
[Pause the video at 2:54] Discuss with a partner why it makes sense that someone closer to the equator will trace out a larger circle than someone farther away from the equator. Do you agree with Claire’s reasoning?
Captions
